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8 Syntax-Directed Operations

In addition to those defined in this section, specialized syntax-directed operations are defined throughout this specification.

8.1 Scope Analysis

8.1.1 Static Semantics: BoundNames

Note

"*default*" is used within this specification as a synthetic name for hoistable anonymous functions that are defined using export declarations.

 BindingIdentifier : Identifier
  1. Return a List whose sole element is the StringValue of Identifier.
 BindingIdentifier : yield
  1. Return a List whose sole element is "yield".
 BindingIdentifier : await
  1. Return a List whose sole element is "await".
 LexicalDeclaration : LetOrConst BindingList ;
  1. Return the BoundNames of BindingList.
 BindingList : BindingList , LexicalBinding
  1. Let names be the BoundNames of BindingList.
  2. Append to names the elements of the BoundNames of LexicalBinding.
  3. Return names.
 LexicalBinding : BindingIdentifier Initializeropt
  1. Return the BoundNames of BindingIdentifier.
 LexicalBinding : BindingPattern Initializer
  1. Return the BoundNames of BindingPattern.
 VariableDeclarationList : VariableDeclarationList , VariableDeclaration
  1. Let names be BoundNames of VariableDeclarationList.
  2. Append to names the elements of BoundNames of VariableDeclaration.
  3. Return names.
 VariableDeclaration : BindingIdentifier Initializeropt
  1. Return the BoundNames of BindingIdentifier.
 VariableDeclaration : BindingPattern Initializer
  1. Return the BoundNames of BindingPattern.
 ObjectBindingPattern : { }
  1. Return a new empty List.
 ObjectBindingPattern : { BindingPropertyList , BindingRestProperty }
  1. Let names be BoundNames of BindingPropertyList.
  2. Append to names the elements of BoundNames of BindingRestProperty.
  3. Return names.
 ArrayBindingPattern : [ Elisionopt ]
  1. Return a new empty List.
 ArrayBindingPattern : [ Elisionopt BindingRestElement ]
  1. Return the BoundNames of BindingRestElement.
 ArrayBindingPattern : [ BindingElementList , Elisionopt ]
  1. Return the BoundNames of BindingElementList.
 ArrayBindingPattern : [ BindingElementList , Elisionopt BindingRestElement ]
  1. Let names be BoundNames of BindingElementList.
  2. Append to names the elements of BoundNames of BindingRestElement.
  3. Return names.
 BindingPropertyList : BindingPropertyList , BindingProperty
  1. Let names be BoundNames of BindingPropertyList.
  2. Append to names the elements of BoundNames of BindingProperty.
  3. Return names.
 BindingElementList : BindingElementList , BindingElisionElement
  1. Let names be BoundNames of BindingElementList.
  2. Append to names the elements of BoundNames of BindingElisionElement.
  3. Return names.
 BindingElisionElement : Elisionopt BindingElement
  1. Return BoundNames of BindingElement.
 BindingProperty : PropertyName : BindingElement
  1. Return the BoundNames of BindingElement.
 SingleNameBinding : BindingIdentifier Initializeropt
  1. Return the BoundNames of BindingIdentifier.
 BindingElement : BindingPattern Initializeropt
  1. Return the BoundNames of BindingPattern.
 ForDeclaration : LetOrConst ForBinding
  1. Return the BoundNames of ForBinding.
 FunctionDeclaration : function BindingIdentifier ( FormalParameters ) { FunctionBody }
  1. Return the BoundNames of BindingIdentifier.
 FunctionDeclaration : function ( FormalParameters ) { FunctionBody }
  1. Return « "*default*" ».
 FormalParameters : [empty]
  1. Return a new empty List.
 FormalParameters : FormalParameterList , FunctionRestParameter
  1. Let names be BoundNames of FormalParameterList.
  2. Append to names the BoundNames of FunctionRestParameter.
  3. Return names.
 FormalParameterList : FormalParameterList , FormalParameter
  1. Let names be BoundNames of FormalParameterList.
  2. Append to names the BoundNames of FormalParameter.
  3. Return names.
 ArrowParameters : CoverParenthesizedExpressionAndArrowParameterList
  1. Let formals be CoveredFormalsList of CoverParenthesizedExpressionAndArrowParameterList.
  2. Return the BoundNames of formals.
 GeneratorDeclaration : function * BindingIdentifier ( FormalParameters ) { GeneratorBody }
  1. Return the BoundNames of BindingIdentifier.
 GeneratorDeclaration : function * ( FormalParameters ) { GeneratorBody }
  1. Return « "*default*" ».
 AsyncGeneratorDeclaration : async function * BindingIdentifier ( FormalParameters ) { AsyncGeneratorBody }
  1. Return the BoundNames of BindingIdentifier.
 AsyncGeneratorDeclaration : async function * ( FormalParameters ) { AsyncGeneratorBody }
  1. Return « "*default*" ».
 ClassDeclaration : class BindingIdentifier ClassTail
  1. Return the BoundNames of BindingIdentifier.
 ClassDeclaration : class ClassTail
  1. Return « "*default*" ».
 AsyncFunctionDeclaration : async function BindingIdentifier ( FormalParameters ) { AsyncFunctionBody }
  1. Return the BoundNames of BindingIdentifier.
 AsyncFunctionDeclaration : async function ( FormalParameters ) { AsyncFunctionBody }
  1. Return « "*default*" ».
 CoverCallExpressionAndAsyncArrowHead : MemberExpression Arguments
  1. Let head be CoveredAsyncArrowHead of CoverCallExpressionAndAsyncArrowHead.
  2. Return the BoundNames of head.
 ImportDeclaration : import ImportClause FromClause ;
  1. Return the BoundNames of ImportClause.
 ImportDeclaration : import ModuleSpecifier ;
  1. Return a new empty List.
 ImportClause : ImportedDefaultBinding , NameSpaceImport
  1. Let names be the BoundNames of ImportedDefaultBinding.
  2. Append to names the elements of the BoundNames of NameSpaceImport.
  3. Return names.
 ImportClause : ImportedDefaultBinding , NamedImports
  1. Let names be the BoundNames of ImportedDefaultBinding.
  2. Append to names the elements of the BoundNames of NamedImports.
  3. Return names.
 NamedImports : { }
  1. Return a new empty List.
 ImportsList : ImportsList , ImportSpecifier
  1. Let names be the BoundNames of ImportsList.
  2. Append to names the elements of the BoundNames of ImportSpecifier.
  3. Return names.
 ImportSpecifier : IdentifierName as ImportedBinding
  1. Return the BoundNames of ImportedBinding.
 ExportDeclaration : export ExportFromClause FromClause ; export NamedExports ;
  1. Return a new empty List.
 ExportDeclaration : export VariableStatement
  1. Return the BoundNames of VariableStatement.
 ExportDeclaration : export Declaration
  1. Return the BoundNames of Declaration.
 ExportDeclaration : export default HoistableDeclaration
  1. Let declarationNames be the BoundNames of HoistableDeclaration.
  2. If declarationNames does not include the element "*default*", append "*default*" to declarationNames.
  3. Return declarationNames.
 ExportDeclaration : export default ClassDeclaration
  1. Let declarationNames be the BoundNames of ClassDeclaration.
  2. If declarationNames does not include the element "*default*", append "*default*" to declarationNames.
  3. Return declarationNames.
 ExportDeclaration : export default AssignmentExpression ;
  1. Return « "*default*" ».

8.1.2 Static Semantics: DeclarationPart

8.1.3 Static Semantics: IsConstantDeclaration

LexicalDeclaration : LetOrConst BindingList ;
  1. Return IsConstantDeclaration of LetOrConst.
 LetOrConst : let
  1. Return false.
 LetOrConst : const
  1. Return true.
 FunctionDeclaration : function BindingIdentifier ( FormalParameters ) { FunctionBody } function ( FormalParameters ) { FunctionBody } GeneratorDeclaration : function * BindingIdentifier ( FormalParameters ) { GeneratorBody } function * ( FormalParameters ) { GeneratorBody } AsyncGeneratorDeclaration : async function * BindingIdentifier ( FormalParameters ) { AsyncGeneratorBody } async function * ( FormalParameters ) { AsyncGeneratorBody } AsyncFunctionDeclaration : async function BindingIdentifier ( FormalParameters ) { AsyncFunctionBody } async function ( FormalParameters ) { AsyncFunctionBody }
  1. Return false.
 ClassDeclaration : class BindingIdentifier ClassTail class ClassTail
  1. Return false.
 ExportDeclaration : export ExportFromClause FromClause ; export NamedExports ; export default AssignmentExpression ;
  1. Return false.
 Note

It is not necessary to treat export default AssignmentExpression as a constant declaration because there is no syntax that permits assignment to the internal bound name used to reference a module's default object.

8.1.4 Static Semantics: LexicallyDeclaredNames

Block : { }
  1. Return a new empty List.
 StatementList : StatementList StatementListItem
  1. Let names be LexicallyDeclaredNames of StatementList.
  2. Append to names the elements of the LexicallyDeclaredNames of StatementListItem.
  3. Return names.
 StatementListItem : Statement
  1. If Statement is Statement : LabelledStatement , return LexicallyDeclaredNames of LabelledStatement.
  2. Return a new empty List.
 StatementListItem : Declaration
  1. Return the BoundNames of Declaration.
 CaseBlock : { }
  1. Return a new empty List.
 CaseBlock : { CaseClausesopt DefaultClause CaseClausesopt }
  1. If the first CaseClauses is present, let names be the LexicallyDeclaredNames of the first CaseClauses.
  2. Else, let names be a new empty List.
  3. Append to names the elements of the LexicallyDeclaredNames of DefaultClause.
  4. If the second CaseClauses is not present, return names.
  5. Return the result of appending to names the elements of the LexicallyDeclaredNames of the second CaseClauses.
 CaseClauses : CaseClauses CaseClause
  1. Let names be LexicallyDeclaredNames of CaseClauses.
  2. Append to names the elements of the LexicallyDeclaredNames of CaseClause.
  3. Return names.
 CaseClause : case Expression : StatementListopt
  1. If the StatementList is present, return the LexicallyDeclaredNames of StatementList.
  2. Return a new empty List.
 DefaultClause : default : StatementListopt
  1. If the StatementList is present, return the LexicallyDeclaredNames of StatementList.
  2. Return a new empty List.
 LabelledStatement : LabelIdentifier : LabelledItem
  1. Return the LexicallyDeclaredNames of LabelledItem.
 LabelledItem : Statement
  1. Return a new empty List.
 LabelledItem : FunctionDeclaration
  1. Return BoundNames of FunctionDeclaration.
 FunctionStatementList : [empty]
  1. Return a new empty List.
 FunctionStatementList : StatementList
  1. Return TopLevelLexicallyDeclaredNames of StatementList.
 ConciseBody : ExpressionBody
  1. Return a new empty List.
 AsyncConciseBody : ExpressionBody
  1. Return a new empty List.
 ScriptBody : StatementList
  1. Return TopLevelLexicallyDeclaredNames of StatementList.
 Note 1

At the top level of a Script, function declarations are treated like var declarations rather than like lexical declarations.

 Note 2

The LexicallyDeclaredNames of a Module includes the names of all of its imported bindings.

 ModuleItemList : ModuleItemList ModuleItem
  1. Let names be LexicallyDeclaredNames of ModuleItemList.
  2. Append to names the elements of the LexicallyDeclaredNames of ModuleItem.
  3. Return names.
 ModuleItem : ImportDeclaration
  1. Return the BoundNames of ImportDeclaration.
 ModuleItem : ExportDeclaration
  1. If ExportDeclaration is export VariableStatement, return a new empty List.
  2. Return the BoundNames of ExportDeclaration.
 ModuleItem : StatementListItem
  1. Return LexicallyDeclaredNames of StatementListItem.
 Note 3

At the top level of a Module, function declarations are treated like lexical declarations rather than like var declarations.

8.1.5 Static Semantics: LexicallyScopedDeclarations

StatementList : StatementList StatementListItem
  1. Let declarations be LexicallyScopedDeclarations of StatementList.
  2. Append to declarations the elements of the LexicallyScopedDeclarations of StatementListItem.
  3. Return declarations.
 StatementListItem : Statement
  1. If Statement is Statement : LabelledStatement , return LexicallyScopedDeclarations of LabelledStatement.
  2. Return a new empty List.
 StatementListItem : Declaration
  1. Return a List whose sole element is DeclarationPart of Declaration.
 CaseBlock : { }
  1. Return a new empty List.
 CaseBlock : { CaseClausesopt DefaultClause CaseClausesopt }
  1. If the first CaseClauses is present, let declarations be the LexicallyScopedDeclarations of the first CaseClauses.
  2. Else, let declarations be a new empty List.
  3. Append to declarations the elements of the LexicallyScopedDeclarations of DefaultClause.
  4. If the second CaseClauses is not present, return declarations.
  5. Return the result of appending to declarations the elements of the LexicallyScopedDeclarations of the second CaseClauses.
 CaseClauses : CaseClauses CaseClause
  1. Let declarations be LexicallyScopedDeclarations of CaseClauses.
  2. Append to declarations the elements of the LexicallyScopedDeclarations of CaseClause.
  3. Return declarations.
 CaseClause : case Expression : StatementListopt
  1. If the StatementList is present, return the LexicallyScopedDeclarations of StatementList.
  2. Return a new empty List.
 DefaultClause : default : StatementListopt
  1. If the StatementList is present, return the LexicallyScopedDeclarations of StatementList.
  2. Return a new empty List.
 LabelledStatement : LabelIdentifier : LabelledItem
  1. Return the LexicallyScopedDeclarations of LabelledItem.
 LabelledItem : Statement
  1. Return a new empty List.
 LabelledItem : FunctionDeclaration
  1. Return a List whose sole element is FunctionDeclaration.
 FunctionStatementList : [empty]
  1. Return a new empty List.
 FunctionStatementList : StatementList
  1. Return the TopLevelLexicallyScopedDeclarations of StatementList.
 ConciseBody : ExpressionBody
  1. Return a new empty List.
 AsyncConciseBody : ExpressionBody
  1. Return a new empty List.
 ScriptBody : StatementList
  1. Return TopLevelLexicallyScopedDeclarations of StatementList.
 Module : [empty]
  1. Return a new empty List.
 ModuleItemList : ModuleItemList ModuleItem
  1. Let declarations be LexicallyScopedDeclarations of ModuleItemList.
  2. Append to declarations the elements of the LexicallyScopedDeclarations of ModuleItem.
  3. Return declarations.
 ModuleItem : ImportDeclaration
  1. Return a new empty List.
 ExportDeclaration : export ExportFromClause FromClause ; export NamedExports ; export VariableStatement
  1. Return a new empty List.
 ExportDeclaration : export Declaration
  1. Return a List whose sole element is DeclarationPart of Declaration.
 ExportDeclaration : export default HoistableDeclaration
  1. Return a List whose sole element is DeclarationPart of HoistableDeclaration.
 ExportDeclaration : export default ClassDeclaration
  1. Return a List whose sole element is ClassDeclaration.
 ExportDeclaration : export default AssignmentExpression ;
  1. Return a List whose sole element is this ExportDeclaration.

8.1.6 Static Semantics: VarDeclaredNames

Statement : EmptyStatement ExpressionStatement ContinueStatement BreakStatement ReturnStatement ThrowStatement DebuggerStatement
  1. Return a new empty List.
 Block : { }
  1. Return a new empty List.
 StatementList : StatementList StatementListItem
  1. Let names be VarDeclaredNames of StatementList.
  2. Append to names the elements of the VarDeclaredNames of StatementListItem.
  3. Return names.
 StatementListItem : Declaration
  1. Return a new empty List.
 VariableStatement : var VariableDeclarationList ;
  1. Return BoundNames of VariableDeclarationList.
 IfStatement : if ( Expression ) Statement else Statement
  1. Let names be VarDeclaredNames of the first Statement.
  2. Append to names the elements of the VarDeclaredNames of the second Statement.
  3. Return names.
 IfStatement : if ( Expression ) Statement
  1. Return the VarDeclaredNames of Statement.
 DoWhileStatement : do Statement while ( Expression ) ;
  1. Return the VarDeclaredNames of Statement.
 WhileStatement : while ( Expression ) Statement
  1. Return the VarDeclaredNames of Statement.
 ForStatement : for ( Expressionopt ; Expressionopt ; Expressionopt ) Statement
  1. Return the VarDeclaredNames of Statement.
 ForStatement : for ( var VariableDeclarationList ; Expressionopt ; Expressionopt ) Statement
  1. Let names be BoundNames of VariableDeclarationList.
  2. Append to names the elements of the VarDeclaredNames of Statement.
  3. Return names.
 ForStatement : for ( LexicalDeclaration Expressionopt ; Expressionopt ) Statement
  1. Return the VarDeclaredNames of Statement.
 ForInOfStatement : for ( LeftHandSideExpression in Expression ) Statement for ( ForDeclaration in Expression ) Statement for ( LeftHandSideExpression of AssignmentExpression ) Statement for ( ForDeclaration of AssignmentExpression ) Statement for await ( LeftHandSideExpression of AssignmentExpression ) Statement for await ( ForDeclaration of AssignmentExpression ) Statement
  1. Return the VarDeclaredNames of Statement.
 ForInOfStatement : for ( var ForBinding in Expression ) Statement for ( var ForBinding of AssignmentExpression ) Statement for await ( var ForBinding of AssignmentExpression ) Statement
  1. Let names be the BoundNames of ForBinding.
  2. Append to names the elements of the VarDeclaredNames of Statement.
  3. Return names.
 Note

This section is extended by Annex B.3.6.

 WithStatement : with ( Expression ) Statement
  1. Return the VarDeclaredNames of Statement.
 SwitchStatement : switch ( Expression ) CaseBlock
  1. Return the VarDeclaredNames of CaseBlock.
 CaseBlock : { }
  1. Return a new empty List.
 CaseBlock : { CaseClausesopt DefaultClause CaseClausesopt }
  1. If the first CaseClauses is present, let names be the VarDeclaredNames of the first CaseClauses.
  2. Else, let names be a new empty List.
  3. Append to names the elements of the VarDeclaredNames of DefaultClause.
  4. If the second CaseClauses is not present, return names.
  5. Return the result of appending to names the elements of the VarDeclaredNames of the second CaseClauses.
 CaseClauses : CaseClauses CaseClause
  1. Let names be VarDeclaredNames of CaseClauses.
  2. Append to names the elements of the VarDeclaredNames of CaseClause.
  3. Return names.
 CaseClause : case Expression : StatementListopt
  1. If the StatementList is present, return the VarDeclaredNames of StatementList.
  2. Return a new empty List.
 DefaultClause : default : StatementListopt
  1. If the StatementList is present, return the VarDeclaredNames of StatementList.
  2. Return a new empty List.
 LabelledStatement : LabelIdentifier : LabelledItem
  1. Return the VarDeclaredNames of LabelledItem.
 LabelledItem : FunctionDeclaration
  1. Return a new empty List.
 TryStatement : try Block Catch
  1. Let names be VarDeclaredNames of Block.
  2. Append to names the elements of the VarDeclaredNames of Catch.
  3. Return names.
 TryStatement : try Block Finally
  1. Let names be VarDeclaredNames of Block.
  2. Append to names the elements of the VarDeclaredNames of Finally.
  3. Return names.
 TryStatement : try Block Catch Finally
  1. Let names be VarDeclaredNames of Block.
  2. Append to names the elements of the VarDeclaredNames of Catch.
  3. Append to names the elements of the VarDeclaredNames of Finally.
  4. Return names.
 Catch : catch ( CatchParameter ) Block
  1. Return the VarDeclaredNames of Block.
 FunctionStatementList : [empty]
  1. Return a new empty List.
 FunctionStatementList : StatementList
  1. Return TopLevelVarDeclaredNames of StatementList.
 ConciseBody : ExpressionBody
  1. Return a new empty List.
 AsyncConciseBody : ExpressionBody
  1. Return a new empty List.
 ScriptBody : StatementList
  1. Return TopLevelVarDeclaredNames of StatementList.
 Module : [empty]
  1. Return a new empty List.
 ModuleItemList : ModuleItemList ModuleItem
  1. Let names be VarDeclaredNames of ModuleItemList.
  2. Append to names the elements of the VarDeclaredNames of ModuleItem.
  3. Return names.
 ModuleItem : ImportDeclaration
  1. Return a new empty List.
 ModuleItem : ExportDeclaration
  1. If ExportDeclaration is export VariableStatement, return BoundNames of ExportDeclaration.
  2. Return a new empty List.

8.1.7 Static Semantics: VarScopedDeclarations

Statement : EmptyStatement ExpressionStatement ContinueStatement BreakStatement ReturnStatement ThrowStatement DebuggerStatement
  1. Return a new empty List.
 Block : { }
  1. Return a new empty List.
 StatementList : StatementList StatementListItem
  1. Let declarations be VarScopedDeclarations of StatementList.
  2. Append to declarations the elements of the VarScopedDeclarations of StatementListItem.
  3. Return declarations.
 StatementListItem : Declaration
  1. Return a new empty List.
 VariableDeclarationList : VariableDeclaration
  1. Return a List whose sole element is VariableDeclaration.
 VariableDeclarationList : VariableDeclarationList , VariableDeclaration
  1. Let declarations be VarScopedDeclarations of VariableDeclarationList.
  2. Append VariableDeclaration to declarations.
  3. Return declarations.
 IfStatement : if ( Expression ) Statement else Statement
  1. Let declarations be VarScopedDeclarations of the first Statement.
  2. Append to declarations the elements of the VarScopedDeclarations of the second Statement.
  3. Return declarations.
 IfStatement : if ( Expression ) Statement
  1. Return the VarScopedDeclarations of Statement.
 DoWhileStatement : do Statement while ( Expression ) ;
  1. Return the VarScopedDeclarations of Statement.
 WhileStatement : while ( Expression ) Statement
  1. Return the VarScopedDeclarations of Statement.
 ForStatement : for ( Expressionopt ; Expressionopt ; Expressionopt ) Statement
  1. Return the VarScopedDeclarations of Statement.
 ForStatement : for ( var VariableDeclarationList ; Expressionopt ; Expressionopt ) Statement
  1. Let declarations be VarScopedDeclarations of VariableDeclarationList.
  2. Append to declarations the elements of the VarScopedDeclarations of Statement.
  3. Return declarations.
 ForStatement : for ( LexicalDeclaration Expressionopt ; Expressionopt ) Statement
  1. Return the VarScopedDeclarations of Statement.
 ForInOfStatement : for ( LeftHandSideExpression in Expression ) Statement for ( ForDeclaration in Expression ) Statement for ( LeftHandSideExpression of AssignmentExpression ) Statement for ( ForDeclaration of AssignmentExpression ) Statement for await ( LeftHandSideExpression of AssignmentExpression ) Statement for await ( ForDeclaration of AssignmentExpression ) Statement
  1. Return the VarScopedDeclarations of Statement.
 ForInOfStatement : for ( var ForBinding in Expression ) Statement for ( var ForBinding of AssignmentExpression ) Statement for await ( var ForBinding of AssignmentExpression ) Statement
  1. Let declarations be a List whose sole element is ForBinding.
  2. Append to declarations the elements of the VarScopedDeclarations of Statement.
  3. Return declarations.
 Note

This section is extended by Annex B.3.6.

 WithStatement : with ( Expression ) Statement
  1. Return the VarScopedDeclarations of Statement.
 SwitchStatement : switch ( Expression ) CaseBlock
  1. Return the VarScopedDeclarations of CaseBlock.
 CaseBlock : { }
  1. Return a new empty List.
 CaseBlock : { CaseClausesopt DefaultClause CaseClausesopt }
  1. If the first CaseClauses is present, let declarations be the VarScopedDeclarations of the first CaseClauses.
  2. Else, let declarations be a new empty List.
  3. Append to declarations the elements of the VarScopedDeclarations of DefaultClause.
  4. If the second CaseClauses is not present, return declarations.
  5. Return the result of appending to declarations the elements of the VarScopedDeclarations of the second CaseClauses.
 CaseClauses : CaseClauses CaseClause
  1. Let declarations be VarScopedDeclarations of CaseClauses.
  2. Append to declarations the elements of the VarScopedDeclarations of CaseClause.
  3. Return declarations.
 CaseClause : case Expression : StatementListopt
  1. If the StatementList is present, return the VarScopedDeclarations of StatementList.
  2. Return a new empty List.
 DefaultClause : default : StatementListopt
  1. If the StatementList is present, return the VarScopedDeclarations of StatementList.
  2. Return a new empty List.
 LabelledStatement : LabelIdentifier : LabelledItem
  1. Return the VarScopedDeclarations of LabelledItem.
 LabelledItem : FunctionDeclaration
  1. Return a new empty List.
 TryStatement : try Block Catch
  1. Let declarations be VarScopedDeclarations of Block.
  2. Append to declarations the elements of the VarScopedDeclarations of Catch.
  3. Return declarations.
 TryStatement : try Block Finally
  1. Let declarations be VarScopedDeclarations of Block.
  2. Append to declarations the elements of the VarScopedDeclarations of Finally.
  3. Return declarations.
 TryStatement : try Block Catch Finally
  1. Let declarations be VarScopedDeclarations of Block.
  2. Append to declarations the elements of the VarScopedDeclarations of Catch.
  3. Append to declarations the elements of the VarScopedDeclarations of Finally.
  4. Return declarations.
 Catch : catch ( CatchParameter ) Block
  1. Return the VarScopedDeclarations of Block.
 FunctionStatementList : [empty]
  1. Return a new empty List.
 FunctionStatementList : StatementList
  1. Return the TopLevelVarScopedDeclarations of StatementList.
 ConciseBody : ExpressionBody
  1. Return a new empty List.
 AsyncConciseBody : ExpressionBody
  1. Return a new empty List.
 ScriptBody : StatementList
  1. Return TopLevelVarScopedDeclarations of StatementList.
 Module : [empty]
  1. Return a new empty List.
 ModuleItemList : ModuleItemList ModuleItem
  1. Let declarations be VarScopedDeclarations of ModuleItemList.
  2. Append to declarations the elements of the VarScopedDeclarations of ModuleItem.
  3. Return declarations.
 ModuleItem : ImportDeclaration
  1. Return a new empty List.
 ModuleItem : ExportDeclaration
  1. If ExportDeclaration is export VariableStatement, return VarScopedDeclarations of VariableStatement.
  2. Return a new empty List.

8.1.8 Static Semantics: TopLevelLexicallyDeclaredNames

StatementList : StatementList StatementListItem
  1. Let names be TopLevelLexicallyDeclaredNames of StatementList.
  2. Append to names the elements of the TopLevelLexicallyDeclaredNames of StatementListItem.
  3. Return names.
 StatementListItem : Statement
  1. Return a new empty List.
 StatementListItem : Declaration
  1. If Declaration is Declaration : HoistableDeclaration , then
    1. Return « ».
  2. Return the BoundNames of Declaration.
 Note

At the top level of a function, or script, function declarations are treated like var declarations rather than like lexical declarations.

 LabelledStatement : LabelIdentifier : LabelledItem
  1. Return a new empty List.

8.1.9 Static Semantics: TopLevelLexicallyScopedDeclarations

Block : { }
  1. Return a new empty List.
 StatementList : StatementList StatementListItem
  1. Let declarations be TopLevelLexicallyScopedDeclarations of StatementList.
  2. Append to declarations the elements of the TopLevelLexicallyScopedDeclarations of StatementListItem.
  3. Return declarations.
 StatementListItem : Statement
  1. Return a new empty List.
 StatementListItem : Declaration
  1. If Declaration is Declaration : HoistableDeclaration , then
    1. Return « ».
  2. Return a List whose sole element is Declaration.
 LabelledStatement : LabelIdentifier : LabelledItem
  1. Return a new empty List.

8.1.10 Static Semantics: TopLevelVarDeclaredNames

Block : { }
  1. Return a new empty List.
 StatementList : StatementList StatementListItem
  1. Let names be TopLevelVarDeclaredNames of StatementList.
  2. Append to names the elements of the TopLevelVarDeclaredNames of StatementListItem.
  3. Return names.
 StatementListItem : Declaration
  1. If Declaration is Declaration : HoistableDeclaration , then
    1. Return the BoundNames of HoistableDeclaration.
  2. Return a new empty List.
 StatementListItem : Statement
  1. If Statement is Statement : LabelledStatement , return TopLevelVarDeclaredNames of Statement.
  2. Return VarDeclaredNames of Statement.
 Note

At the top level of a function or script, inner function declarations are treated like var declarations.

 LabelledStatement : LabelIdentifier : LabelledItem
  1. Return the TopLevelVarDeclaredNames of LabelledItem.
 LabelledItem : Statement
  1. If Statement is Statement : LabelledStatement , return TopLevelVarDeclaredNames of Statement.
  2. Return VarDeclaredNames of Statement.
 LabelledItem : FunctionDeclaration
  1. Return BoundNames of FunctionDeclaration.

8.1.11 Static Semantics: TopLevelVarScopedDeclarations

Block : { }
  1. Return a new empty List.
 StatementList : StatementList StatementListItem
  1. Let declarations be TopLevelVarScopedDeclarations of StatementList.
  2. Append to declarations the elements of the TopLevelVarScopedDeclarations of StatementListItem.
  3. Return declarations.
 StatementListItem : Statement
  1. If Statement is Statement : LabelledStatement , return TopLevelVarScopedDeclarations of Statement.
  2. Return VarScopedDeclarations of Statement.
 StatementListItem : Declaration
  1. If Declaration is Declaration : HoistableDeclaration , then
    1. Let declaration be DeclarationPart of HoistableDeclaration.
    2. Return « declaration ».
  2. Return a new empty List.
 LabelledStatement : LabelIdentifier : LabelledItem
  1. Return the TopLevelVarScopedDeclarations of LabelledItem.
 LabelledItem : Statement
  1. If Statement is Statement : LabelledStatement , return TopLevelVarScopedDeclarations of Statement.
  2. Return VarScopedDeclarations of Statement.
 LabelledItem : FunctionDeclaration
  1. Return a List whose sole element is FunctionDeclaration.

8.2 Labels

8.2.1 Static Semantics: ContainsDuplicateLabels

With parameter labelSet.

Statement : VariableStatement EmptyStatement ExpressionStatement ContinueStatement BreakStatement ReturnStatement ThrowStatement DebuggerStatement Block : { } StatementListItem : Declaration
  1. Return false.
 StatementList : StatementList StatementListItem
  1. Let hasDuplicates be ContainsDuplicateLabels of StatementList with argument labelSet.
  2. If hasDuplicates is true, return true.
  3. Return ContainsDuplicateLabels of StatementListItem with argument labelSet.
 IfStatement : if ( Expression ) Statement else Statement
  1. Let hasDuplicate be ContainsDuplicateLabels of the first Statement with argument labelSet.
  2. If hasDuplicate is true, return true.
  3. Return ContainsDuplicateLabels of the second Statement with argument labelSet.
 IfStatement : if ( Expression ) Statement
  1. Return ContainsDuplicateLabels of Statement with argument labelSet.
 DoWhileStatement : do Statement while ( Expression ) ;
  1. Return ContainsDuplicateLabels of Statement with argument labelSet.
 WhileStatement : while ( Expression ) Statement
  1. Return ContainsDuplicateLabels of Statement with argument labelSet.
 ForStatement : for ( Expressionopt ; Expressionopt ; Expressionopt ) Statement for ( var VariableDeclarationList ; Expressionopt ; Expressionopt ) Statement for ( LexicalDeclaration Expressionopt ; Expressionopt ) Statement
  1. Return ContainsDuplicateLabels of Statement with argument labelSet.
 ForInOfStatement : for ( LeftHandSideExpression in Expression ) Statement for ( var ForBinding in Expression ) Statement for ( ForDeclaration in Expression ) Statement for ( LeftHandSideExpression of AssignmentExpression ) Statement for ( var ForBinding of AssignmentExpression ) Statement for ( ForDeclaration of AssignmentExpression ) Statement for await ( LeftHandSideExpression of AssignmentExpression ) Statement for await ( var ForBinding of AssignmentExpression ) Statement for await ( ForDeclaration of AssignmentExpression ) Statement
  1. Return ContainsDuplicateLabels of Statement with argument labelSet.
 Note

This section is extended by Annex B.3.6.

 WithStatement : with ( Expression ) Statement
  1. Return ContainsDuplicateLabels of Statement with argument labelSet.
 SwitchStatement : switch ( Expression ) CaseBlock
  1. Return ContainsDuplicateLabels of CaseBlock with argument labelSet.
 CaseBlock : { }
  1. Return false.
 CaseBlock : { CaseClausesopt DefaultClause CaseClausesopt }
  1. If the first CaseClauses is present, then
    1. Let hasDuplicates be ContainsDuplicateLabels of the first CaseClauses with argument labelSet.
    2. If hasDuplicates is true, return true.
  2. Let hasDuplicates be ContainsDuplicateLabels of DefaultClause with argument labelSet.
  3. If hasDuplicates is true, return true.
  4. If the second CaseClauses is not present, return false.
  5. Return ContainsDuplicateLabels of the second CaseClauses with argument labelSet.
 CaseClauses : CaseClauses CaseClause
  1. Let hasDuplicates be ContainsDuplicateLabels of CaseClauses with argument labelSet.
  2. If hasDuplicates is true, return true.
  3. Return ContainsDuplicateLabels of CaseClause with argument labelSet.
 CaseClause : case Expression : StatementListopt
  1. If the StatementList is present, return ContainsDuplicateLabels of StatementList with argument labelSet.
  2. Return false.
 DefaultClause : default : StatementListopt
  1. If the StatementList is present, return ContainsDuplicateLabels of StatementList with argument labelSet.
  2. Return false.
 LabelledStatement : LabelIdentifier : LabelledItem
  1. Let label be the StringValue of LabelIdentifier.
  2. If label is an element of labelSet, return true.
  3. Let newLabelSet be a copy of labelSet with label appended.
  4. Return ContainsDuplicateLabels of LabelledItem with argument newLabelSet.
 LabelledItem : FunctionDeclaration
  1. Return false.
 TryStatement : try Block Catch
  1. Let hasDuplicates be ContainsDuplicateLabels of Block with argument labelSet.
  2. If hasDuplicates is true, return true.
  3. Return ContainsDuplicateLabels of Catch with argument labelSet.
 TryStatement : try Block Finally
  1. Let hasDuplicates be ContainsDuplicateLabels of Block with argument labelSet.
  2. If hasDuplicates is true, return true.
  3. Return ContainsDuplicateLabels of Finally with argument labelSet.
 TryStatement : try Block Catch Finally
  1. Let hasDuplicates be ContainsDuplicateLabels of Block with argument labelSet.
  2. If hasDuplicates is true, return true.
  3. Let hasDuplicates be ContainsDuplicateLabels of Catch with argument labelSet.
  4. If hasDuplicates is true, return true.
  5. Return ContainsDuplicateLabels of Finally with argument labelSet.
 Catch : catch ( CatchParameter ) Block
  1. Return ContainsDuplicateLabels of Block with argument labelSet.
 FunctionStatementList : [empty]
  1. Return false.
 ModuleItemList : ModuleItemList ModuleItem
  1. Let hasDuplicates be ContainsDuplicateLabels of ModuleItemList with argument labelSet.
  2. If hasDuplicates is true, return true.
  3. Return ContainsDuplicateLabels of ModuleItem with argument labelSet.
 ModuleItem : ImportDeclaration ExportDeclaration
  1. Return false.

8.2.2 Static Semantics: ContainsUndefinedBreakTarget

With parameter labelSet.

Statement : VariableStatement EmptyStatement ExpressionStatement ContinueStatement ReturnStatement ThrowStatement DebuggerStatement Block : { } StatementListItem : Declaration
  1. Return false.
 StatementList : StatementList StatementListItem
  1. Let hasUndefinedLabels be ContainsUndefinedBreakTarget of StatementList with argument labelSet.
  2. If hasUndefinedLabels is true, return true.
  3. Return ContainsUndefinedBreakTarget of StatementListItem with argument labelSet.
 IfStatement : if ( Expression ) Statement else Statement
  1. Let hasUndefinedLabels be ContainsUndefinedBreakTarget of the first Statement with argument labelSet.
  2. If hasUndefinedLabels is true, return true.
  3. Return ContainsUndefinedBreakTarget of the second Statement with argument labelSet.
 IfStatement : if ( Expression ) Statement
  1. Return ContainsUndefinedBreakTarget of Statement with argument labelSet.
 DoWhileStatement : do Statement while ( Expression ) ;
  1. Return ContainsUndefinedBreakTarget of Statement with argument labelSet.
 WhileStatement : while ( Expression ) Statement
  1. Return ContainsUndefinedBreakTarget of Statement with argument labelSet.
 ForStatement : for ( Expressionopt ; Expressionopt ; Expressionopt ) Statement for ( var VariableDeclarationList ; Expressionopt ; Expressionopt ) Statement for ( LexicalDeclaration Expressionopt ; Expressionopt ) Statement
  1. Return ContainsUndefinedBreakTarget of Statement with argument labelSet.
 ForInOfStatement : for ( LeftHandSideExpression in Expression ) Statement for ( var ForBinding in Expression ) Statement for ( ForDeclaration in Expression ) Statement for ( LeftHandSideExpression of AssignmentExpression ) Statement for ( var ForBinding of AssignmentExpression ) Statement for ( ForDeclaration of AssignmentExpression ) Statement for await ( LeftHandSideExpression of AssignmentExpression ) Statement for await ( var ForBinding of AssignmentExpression ) Statement for await ( ForDeclaration of AssignmentExpression ) Statement
  1. Return ContainsUndefinedBreakTarget of Statement with argument labelSet.
 Note

This section is extended by Annex B.3.6.

 BreakStatement : break ;
  1. Return false.
 BreakStatement : break LabelIdentifier ;
  1. If the StringValue of LabelIdentifier is not an element of labelSet, return true.
  2. Return false.
 WithStatement : with ( Expression ) Statement
  1. Return ContainsUndefinedBreakTarget of Statement with argument labelSet.
 SwitchStatement : switch ( Expression ) CaseBlock
  1. Return ContainsUndefinedBreakTarget of CaseBlock with argument labelSet.
 CaseBlock : { }
  1. Return false.
 CaseBlock : { CaseClausesopt DefaultClause CaseClausesopt }
  1. If the first CaseClauses is present, then
    1. Let hasUndefinedLabels be ContainsUndefinedBreakTarget of the first CaseClauses with argument labelSet.
    2. If hasUndefinedLabels is true, return true.
  2. Let hasUndefinedLabels be ContainsUndefinedBreakTarget of DefaultClause with argument labelSet.
  3. If hasUndefinedLabels is true, return true.
  4. If the second CaseClauses is not present, return false.
  5. Return ContainsUndefinedBreakTarget of the second CaseClauses with argument labelSet.
 CaseClauses : CaseClauses CaseClause
  1. Let hasUndefinedLabels be ContainsUndefinedBreakTarget of CaseClauses with argument labelSet.
  2. If hasUndefinedLabels is true, return true.
  3. Return ContainsUndefinedBreakTarget of CaseClause with argument labelSet.
 CaseClause : case Expression : StatementListopt
  1. If the StatementList is present, return ContainsUndefinedBreakTarget of StatementList with argument labelSet.
  2. Return false.
 DefaultClause : default : StatementListopt
  1. If the StatementList is present, return ContainsUndefinedBreakTarget of StatementList with argument labelSet.
  2. Return false.
 LabelledStatement : LabelIdentifier : LabelledItem
  1. Let label be the StringValue of LabelIdentifier.
  2. Let newLabelSet be a copy of labelSet with label appended.
  3. Return ContainsUndefinedBreakTarget of LabelledItem with argument newLabelSet.
 LabelledItem : FunctionDeclaration
  1. Return false.
 TryStatement : try Block Catch
  1. Let hasUndefinedLabels be ContainsUndefinedBreakTarget of Block with argument labelSet.
  2. If hasUndefinedLabels is true, return true.
  3. Return ContainsUndefinedBreakTarget of Catch with argument labelSet.
 TryStatement : try Block Finally
  1. Let hasUndefinedLabels be ContainsUndefinedBreakTarget of Block with argument labelSet.
  2. If hasUndefinedLabels is true, return true.
  3. Return ContainsUndefinedBreakTarget of Finally with argument labelSet.
 TryStatement : try Block Catch Finally
  1. Let hasUndefinedLabels be ContainsUndefinedBreakTarget of Block with argument labelSet.
  2. If hasUndefinedLabels is true, return true.
  3. Let hasUndefinedLabels be ContainsUndefinedBreakTarget of Catch with argument labelSet.
  4. If hasUndefinedLabels is true, return true.
  5. Return ContainsUndefinedBreakTarget of Finally with argument labelSet.
 Catch : catch ( CatchParameter ) Block
  1. Return ContainsUndefinedBreakTarget of Block with argument labelSet.
 FunctionStatementList : [empty]
  1. Return false.
 ModuleItemList : ModuleItemList ModuleItem
  1. Let hasUndefinedLabels be ContainsUndefinedBreakTarget of ModuleItemList with argument labelSet.
  2. If hasUndefinedLabels is true, return true.
  3. Return ContainsUndefinedBreakTarget of ModuleItem with argument labelSet.
 ModuleItem : ImportDeclaration ExportDeclaration
  1. Return false.

8.2.3 Static Semantics: ContainsUndefinedContinueTarget

With parameters iterationSet and labelSet.

Statement : VariableStatement EmptyStatement ExpressionStatement BreakStatement ReturnStatement ThrowStatement DebuggerStatement Block : { } StatementListItem : Declaration
  1. Return false.
 BreakableStatement : IterationStatement
  1. Let newIterationSet be a copy of iterationSet with all the elements of labelSet appended.
  2. Return ContainsUndefinedContinueTarget of IterationStatement with arguments newIterationSet and « ».
 StatementList : StatementList StatementListItem
  1. Let hasUndefinedLabels be ContainsUndefinedContinueTarget of StatementList with arguments iterationSet and « ».
  2. If hasUndefinedLabels is true, return true.
  3. Return ContainsUndefinedContinueTarget of StatementListItem with arguments iterationSet and « ».
 IfStatement : if ( Expression ) Statement else Statement
  1. Let hasUndefinedLabels be ContainsUndefinedContinueTarget of the first Statement with arguments iterationSet and « ».
  2. If hasUndefinedLabels is true, return true.
  3. Return ContainsUndefinedContinueTarget of the second Statement with arguments iterationSet and « ».
 IfStatement : if ( Expression ) Statement
  1. Return ContainsUndefinedContinueTarget of Statement with arguments iterationSet and « ».
 DoWhileStatement : do Statement while ( Expression ) ;
  1. Return ContainsUndefinedContinueTarget of Statement with arguments iterationSet and « ».
 WhileStatement : while ( Expression ) Statement
  1. Return ContainsUndefinedContinueTarget of Statement with arguments iterationSet and « ».
 ForStatement : for ( Expressionopt ; Expressionopt ; Expressionopt ) Statement for ( var VariableDeclarationList ; Expressionopt ; Expressionopt ) Statement for ( LexicalDeclaration Expressionopt ; Expressionopt ) Statement
  1. Return ContainsUndefinedContinueTarget of Statement with arguments iterationSet and « ».
 ForInOfStatement : for ( LeftHandSideExpression in Expression ) Statement for ( var ForBinding in Expression ) Statement for ( ForDeclaration in Expression ) Statement for ( LeftHandSideExpression of AssignmentExpression ) Statement for ( var ForBinding of AssignmentExpression ) Statement for ( ForDeclaration of AssignmentExpression ) Statement for await ( LeftHandSideExpression of AssignmentExpression ) Statement for await ( var ForBinding of AssignmentExpression ) Statement for await ( ForDeclaration of AssignmentExpression ) Statement
  1. Return ContainsUndefinedContinueTarget of Statement with arguments iterationSet and « ».
 Note

This section is extended by Annex B.3.6.

 ContinueStatement : continue ;
  1. Return false.
 ContinueStatement : continue LabelIdentifier ;
  1. If the StringValue of LabelIdentifier is not an element of iterationSet, return true.
  2. Return false.
 WithStatement : with ( Expression ) Statement
  1. Return ContainsUndefinedContinueTarget of Statement with arguments iterationSet and « ».
 SwitchStatement : switch ( Expression ) CaseBlock
  1. Return ContainsUndefinedContinueTarget of CaseBlock with arguments iterationSet and « ».
 CaseBlock : { }
  1. Return false.
 CaseBlock : { CaseClausesopt DefaultClause CaseClausesopt }
  1. If the first CaseClauses is present, then
    1. Let hasUndefinedLabels be ContainsUndefinedContinueTarget of the first CaseClauses with arguments iterationSet and « ».
    2. If hasUndefinedLabels is true, return true.
  2. Let hasUndefinedLabels be ContainsUndefinedContinueTarget of DefaultClause with arguments iterationSet and « ».
  3. If hasUndefinedLabels is true, return true.
  4. If the second CaseClauses is not present, return false.
  5. Return ContainsUndefinedContinueTarget of the second CaseClauses with arguments iterationSet and « ».
 CaseClauses : CaseClauses CaseClause
  1. Let hasUndefinedLabels be ContainsUndefinedContinueTarget of CaseClauses with arguments iterationSet and « ».
  2. If hasUndefinedLabels is true, return true.
  3. Return ContainsUndefinedContinueTarget of CaseClause with arguments iterationSet and « ».
 CaseClause : case Expression : StatementListopt
  1. If the StatementList is present, return ContainsUndefinedContinueTarget of StatementList with arguments iterationSet and « ».
  2. Return false.
 DefaultClause : default : StatementListopt
  1. If the StatementList is present, return ContainsUndefinedContinueTarget of StatementList with arguments iterationSet and « ».
  2. Return false.
 LabelledStatement : LabelIdentifier : LabelledItem
  1. Let label be the StringValue of LabelIdentifier.
  2. Let newLabelSet be a copy of labelSet with label appended.
  3. Return ContainsUndefinedContinueTarget of LabelledItem with arguments iterationSet and newLabelSet.
 LabelledItem : FunctionDeclaration
  1. Return false.
 TryStatement : try Block Catch
  1. Let hasUndefinedLabels be ContainsUndefinedContinueTarget of Block with arguments iterationSet and « ».
  2. If hasUndefinedLabels is true, return true.
  3. Return ContainsUndefinedContinueTarget of Catch with arguments iterationSet and « ».
 TryStatement : try Block Finally
  1. Let hasUndefinedLabels be ContainsUndefinedContinueTarget of Block with arguments iterationSet and « ».
  2. If hasUndefinedLabels is true, return true.
  3. Return ContainsUndefinedContinueTarget of Finally with arguments iterationSet and « ».
 TryStatement : try Block Catch Finally
  1. Let hasUndefinedLabels be ContainsUndefinedContinueTarget of Block with arguments iterationSet and « ».
  2. If hasUndefinedLabels is true, return true.
  3. Let hasUndefinedLabels be ContainsUndefinedContinueTarget of Catch with arguments iterationSet and « ».
  4. If hasUndefinedLabels is true, return true.
  5. Return ContainsUndefinedContinueTarget of Finally with arguments iterationSet and « ».
 Catch : catch ( CatchParameter ) Block
  1. Return ContainsUndefinedContinueTarget of Block with arguments iterationSet and « ».
 FunctionStatementList : [empty]
  1. Return false.
 ModuleItemList : ModuleItemList ModuleItem
  1. Let hasUndefinedLabels be ContainsUndefinedContinueTarget of ModuleItemList with arguments iterationSet and « ».
  2. If hasUndefinedLabels is true, return true.
  3. Return ContainsUndefinedContinueTarget of ModuleItem with arguments iterationSet and « ».
 ModuleItem : ImportDeclaration ExportDeclaration
  1. Return false.

8.3 Function Name Inference

8.3.1 Static Semantics: HasName

PrimaryExpression : CoverParenthesizedExpressionAndArrowParameterList
  1. Let expr be CoveredParenthesizedExpression of CoverParenthesizedExpressionAndArrowParameterList.
  2. If IsFunctionDefinition of expr is false, return false.
  3. Return HasName of expr.
 FunctionExpression : function ( FormalParameters ) { FunctionBody } GeneratorExpression : function * ( FormalParameters ) { GeneratorBody } AsyncGeneratorExpression : async function * ( FormalParameters ) { AsyncGeneratorBody } AsyncFunctionExpression : async function ( FormalParameters ) { AsyncFunctionBody } ArrowFunction : ArrowParameters => ConciseBody AsyncArrowFunction : async AsyncArrowBindingIdentifier => AsyncConciseBody CoverCallExpressionAndAsyncArrowHead => AsyncConciseBody ClassExpression : class ClassTail
  1. Return false.
 FunctionExpression : function BindingIdentifier ( FormalParameters ) { FunctionBody } GeneratorExpression : function * BindingIdentifier ( FormalParameters ) { GeneratorBody } AsyncGeneratorExpression : async function * BindingIdentifier ( FormalParameters ) { AsyncGeneratorBody } AsyncFunctionExpression : async function BindingIdentifier ( FormalParameters ) { AsyncFunctionBody } ClassExpression : class BindingIdentifier ClassTail
  1. Return true.

8.3.2 Static Semantics: IsFunctionDefinition

PrimaryExpression : CoverParenthesizedExpressionAndArrowParameterList
  1. Let expr be CoveredParenthesizedExpression of CoverParenthesizedExpressionAndArrowParameterList.
  2. Return IsFunctionDefinition of expr.
 PrimaryExpression : this IdentifierReference Literal ArrayLiteral ObjectLiteral RegularExpressionLiteral TemplateLiteral MemberExpression : MemberExpression [ Expression ] MemberExpression . IdentifierName MemberExpression TemplateLiteral SuperProperty MetaProperty new MemberExpression Arguments NewExpression : new NewExpression LeftHandSideExpression : CallExpression OptionalExpression UpdateExpression : LeftHandSideExpression ++ LeftHandSideExpression -- ++ UnaryExpression -- UnaryExpression UnaryExpression : delete UnaryExpression void UnaryExpression typeof UnaryExpression + UnaryExpression - UnaryExpression ~ UnaryExpression ! UnaryExpression AwaitExpression ExponentiationExpression : UpdateExpression ** ExponentiationExpression MultiplicativeExpression : MultiplicativeExpression MultiplicativeOperator ExponentiationExpression AdditiveExpression : AdditiveExpression + MultiplicativeExpression AdditiveExpression - MultiplicativeExpression ShiftExpression : ShiftExpression << AdditiveExpression ShiftExpression >> AdditiveExpression ShiftExpression >>> AdditiveExpression RelationalExpression : RelationalExpression < ShiftExpression RelationalExpression > ShiftExpression RelationalExpression <= ShiftExpression RelationalExpression >= ShiftExpression RelationalExpression instanceof ShiftExpression RelationalExpression in ShiftExpression EqualityExpression : EqualityExpression == RelationalExpression EqualityExpression != RelationalExpression EqualityExpression === RelationalExpression EqualityExpression !== RelationalExpression BitwiseANDExpression : BitwiseANDExpression & EqualityExpression BitwiseXORExpression : BitwiseXORExpression ^ BitwiseANDExpression BitwiseORExpression : BitwiseORExpression | BitwiseXORExpression LogicalANDExpression : LogicalANDExpression && BitwiseORExpression LogicalORExpression : LogicalORExpression || LogicalANDExpression CoalesceExpression : CoalesceExpressionHead ?? BitwiseORExpression ConditionalExpression : ShortCircuitExpression ? AssignmentExpression : AssignmentExpression AssignmentExpression : YieldExpression LeftHandSideExpression = AssignmentExpression LeftHandSideExpression AssignmentOperator AssignmentExpression LeftHandSideExpression &&= AssignmentExpression LeftHandSideExpression ||= AssignmentExpression LeftHandSideExpression ??= AssignmentExpression Expression : Expression , AssignmentExpression
  1. Return false.
 AssignmentExpression : ArrowFunction AsyncArrowFunction FunctionExpression : function BindingIdentifieropt ( FormalParameters ) { FunctionBody } GeneratorExpression : function * BindingIdentifieropt ( FormalParameters ) { GeneratorBody } AsyncGeneratorExpression : async function * BindingIdentifieropt ( FormalParameters ) { AsyncGeneratorBody } AsyncFunctionExpression : async function BindingIdentifieropt ( FormalParameters ) { AsyncFunctionBody } ClassExpression : class BindingIdentifieropt ClassTail
  1. Return true.

8.3.3 Static Semantics: IsAnonymousFunctionDefinition ( expr )

The abstract operation IsAnonymousFunctionDefinition takes argument expr (a Parse Node for AssignmentExpression or a Parse Node for Initializer). It determines if its argument is a function definition that does not bind a name. It performs the following steps when called:

  1. If IsFunctionDefinition of expr is false, return false.
  2. Let hasName be HasName of expr.
  3. If hasName is true, return false.
  4. Return true.

8.3.4 Static Semantics: IsIdentifierRef

8.3.5 Runtime Semantics: NamedEvaluation

With parameter name.

PrimaryExpression : CoverParenthesizedExpressionAndArrowParameterList
  1. Let expr be CoveredParenthesizedExpression of CoverParenthesizedExpressionAndArrowParameterList.
  2. Return the result of performing NamedEvaluation for expr with argument name.
 ParenthesizedExpression : ( Expression )
  1. Assert: IsAnonymousFunctionDefinition(Expression) is true.
  2. Return the result of performing NamedEvaluation for Expression with argument name.
 FunctionExpression : function ( FormalParameters ) { FunctionBody }
  1. Return InstantiateOrdinaryFunctionExpression of FunctionExpression with argument name.
 GeneratorExpression : function * ( FormalParameters ) { GeneratorBody }
  1. Return InstantiateGeneratorFunctionExpression of GeneratorExpression with argument name.
 AsyncGeneratorExpression : async function * ( FormalParameters ) { AsyncGeneratorBody }
  1. Return InstantiateAsyncGeneratorFunctionExpression of AsyncGeneratorExpression with argument name.
 AsyncFunctionExpression : async function ( FormalParameters ) { AsyncFunctionBody }
  1. Return InstantiateAsyncFunctionExpression of AsyncFunctionExpression with argument name.
 ArrowFunction : ArrowParameters => ConciseBody
  1. Return InstantiateArrowFunctionExpression of ArrowFunction with argument name.
 AsyncArrowFunction : async AsyncArrowBindingIdentifier => AsyncConciseBody CoverCallExpressionAndAsyncArrowHead => AsyncConciseBody
  1. Return InstantiateAsyncArrowFunctionExpression of AsyncArrowFunction with argument name.
 ClassExpression : class ClassTail
  1. Let value be the result of ClassDefinitionEvaluation of ClassTail with arguments undefined and name.
  2. ReturnIfAbrupt(value).
  3. Set value.[[SourceText]] to the source text matched by ClassExpression.
  4. Return value.

8.4 Contains

8.4.1 Static Semantics: Contains

With parameter symbol.

Every grammar production alternative in this specification which is not listed below implicitly has the following default definition of Contains:

  1. For each child node child of this Parse Node, do
    1. If child is an instance of symbol, return true.
    2. If child is an instance of a nonterminal, then
      1. Let contained be the result of child Contains symbol.
      2. If contained is true, return true.
  2. Return false.
 FunctionDeclaration : function BindingIdentifier ( FormalParameters ) { FunctionBody } function ( FormalParameters ) { FunctionBody } FunctionExpression : function BindingIdentifieropt ( FormalParameters ) { FunctionBody } GeneratorDeclaration : function * BindingIdentifier ( FormalParameters ) { GeneratorBody } function * ( FormalParameters ) { GeneratorBody } GeneratorExpression : function * BindingIdentifieropt ( FormalParameters ) { GeneratorBody } AsyncGeneratorDeclaration : async function * BindingIdentifier ( FormalParameters ) { AsyncGeneratorBody } async function * ( FormalParameters ) { AsyncGeneratorBody } AsyncGeneratorExpression : async function * BindingIdentifieropt ( FormalParameters ) { AsyncGeneratorBody } AsyncFunctionDeclaration : async function BindingIdentifier ( FormalParameters ) { AsyncFunctionBody } async function ( FormalParameters ) { AsyncFunctionBody } AsyncFunctionExpression : async function BindingIdentifieropt ( FormalParameters ) { AsyncFunctionBody }
  1. Return false.
 Note 1

Static semantic rules that depend upon substructure generally do not look into function definitions.

 ClassTail : ClassHeritageopt { ClassBody }
  1. If symbol is ClassBody, return true.
  2. If symbol is ClassHeritage, then
    1. If ClassHeritage is present, return true; otherwise return false.
  3. Let inHeritage be ClassHeritage Contains symbol.
  4. If inHeritage is true, return true.
  5. Return the result of ComputedPropertyContains for ClassBody with argument symbol.
 Note 2

Static semantic rules that depend upon substructure generally do not look into class bodies except for PropertyNames.

 ArrowFunction : ArrowParameters => ConciseBody
  1. If symbol is not one of NewTarget, SuperProperty, SuperCall, super or this, return false.
  2. If ArrowParameters Contains symbol is true, return true.
  3. Return ConciseBody Contains symbol.
 ArrowParameters : CoverParenthesizedExpressionAndArrowParameterList
  1. Let formals be CoveredFormalsList of CoverParenthesizedExpressionAndArrowParameterList.
  2. Return formals Contains symbol.
 AsyncArrowFunction : async AsyncArrowBindingIdentifier => AsyncConciseBody
  1. If symbol is not one of NewTarget, SuperProperty, SuperCall, super, or this, return false.
  2. Return AsyncConciseBody Contains symbol.
 AsyncArrowFunction : CoverCallExpressionAndAsyncArrowHead => AsyncConciseBody
  1. If symbol is not one of NewTarget, SuperProperty, SuperCall, super, or this, return false.
  2. Let head be CoveredAsyncArrowHead of CoverCallExpressionAndAsyncArrowHead.
  3. If head Contains symbol is true, return true.
  4. Return AsyncConciseBody Contains symbol.
 Note 3

Contains is used to detect new.target, this, and super usage within an ArrowFunction or AsyncArrowFunction.

 PropertyDefinition : MethodDefinition
  1. If symbol is MethodDefinition, return true.
  2. Return the result of ComputedPropertyContains for MethodDefinition with argument symbol.
 LiteralPropertyName : IdentifierName
  1. Return false.
 MemberExpression : MemberExpression . IdentifierName
  1. If MemberExpression Contains symbol is true, return true.
  2. Return false.
 SuperProperty : super . IdentifierName
  1. If symbol is the ReservedWord super, return true.
  2. Return false.
 CallExpression : CallExpression . IdentifierName
  1. If CallExpression Contains symbol is true, return true.
  2. Return false.
 OptionalChain : ?. IdentifierName
  1. Return false.
 OptionalChain : OptionalChain . IdentifierName
  1. If OptionalChain Contains symbol is true, return true.
  2. Return false.

8.4.2 Static Semantics: ComputedPropertyContains

With parameter symbol.

PropertyName : LiteralPropertyName
  1. Return false.
 PropertyName : ComputedPropertyName
  1. Return the result of ComputedPropertyName Contains symbol.
 MethodDefinition : PropertyName ( UniqueFormalParameters ) { FunctionBody } get PropertyName ( ) { FunctionBody } set PropertyName ( PropertySetParameterList ) { FunctionBody }
  1. Return the result of ComputedPropertyContains for PropertyName with argument symbol.
 GeneratorMethod : * PropertyName ( UniqueFormalParameters ) { GeneratorBody }
  1. Return the result of ComputedPropertyContains for PropertyName with argument symbol.
 AsyncGeneratorMethod : async * PropertyName ( UniqueFormalParameters ) { AsyncGeneratorBody }
  1. Return the result of ComputedPropertyContains for PropertyName with argument symbol.
 ClassElementList : ClassElementList ClassElement
  1. Let inList be ComputedPropertyContains of ClassElementList with argument symbol.
  2. If inList is true, return true.
  3. Return the result of ComputedPropertyContains for ClassElement with argument symbol.
 ClassElement : ;
  1. Return false.
 AsyncMethod : async PropertyName ( UniqueFormalParameters ) { AsyncFunctionBody }
  1. Return the result of ComputedPropertyContains for PropertyName with argument symbol.

8.5 Miscellaneous

These operations are used in multiple places throughout the specification.

8.5.1 Runtime Semantics: InstantiateFunctionObject

With parameter scope.

FunctionDeclaration : function BindingIdentifier ( FormalParameters ) { FunctionBody } function ( FormalParameters ) { FunctionBody }
  1. Return ? InstantiateOrdinaryFunctionObject of FunctionDeclaration with argument scope.
 GeneratorDeclaration : function * BindingIdentifier ( FormalParameters ) { GeneratorBody } function * ( FormalParameters ) { GeneratorBody }
  1. Return ? InstantiateGeneratorFunctionObject of GeneratorDeclaration with argument scope.
 AsyncGeneratorDeclaration : async function * BindingIdentifier ( FormalParameters ) { AsyncGeneratorBody } async function * ( FormalParameters ) { AsyncGeneratorBody }
  1. Return ? InstantiateAsyncGeneratorFunctionObject of AsyncGeneratorDeclaration with argument scope.
 AsyncFunctionDeclaration : async function BindingIdentifier ( FormalParameters ) { AsyncFunctionBody } async function ( FormalParameters ) { AsyncFunctionBody }
  1. Return ? InstantiateAsyncFunctionObject of AsyncFunctionDeclaration with argument scope.

8.5.2 Runtime Semantics: BindingInitialization

With parameters value and environment.

Note

undefined is passed for environment to indicate that a PutValue operation should be used to assign the initialization value. This is the case for var statements and formal parameter lists of some non-strict functions (See 10.2.10). In those cases a lexical binding is hoisted and preinitialized prior to evaluation of its initializer.

 BindingIdentifier : Identifier
  1. Let name be StringValue of Identifier.
  2. Return ? InitializeBoundName(name, value, environment).
 BindingIdentifier : yield
  1. Return ? InitializeBoundName("yield", value, environment).
 BindingIdentifier : await
  1. Return ? InitializeBoundName("await", value, environment).
 BindingPattern : ObjectBindingPattern
  1. Perform ? RequireObjectCoercible(value).
  2. Return the result of performing BindingInitialization for ObjectBindingPattern using value and environment as arguments.
 BindingPattern : ArrayBindingPattern
  1. Let iteratorRecord be ? GetIterator(value).
  2. Let result be IteratorBindingInitialization of ArrayBindingPattern with arguments iteratorRecord and environment.
  3. If iteratorRecord.[[Done]] is false, return ? IteratorClose(iteratorRecord, result).
  4. Return result.
 ObjectBindingPattern : { }
  1. Return NormalCompletion(empty).
 ObjectBindingPattern : { BindingPropertyList } { BindingPropertyList , }
  1. Perform ? PropertyBindingInitialization for BindingPropertyList using value and environment as the arguments.
  2. Return NormalCompletion(empty).
 ObjectBindingPattern : { BindingRestProperty }
  1. Let excludedNames be a new empty List.
  2. Return the result of performing RestBindingInitialization of BindingRestProperty with value, environment, and excludedNames as the arguments.
 ObjectBindingPattern : { BindingPropertyList , BindingRestProperty }
  1. Let excludedNames be ? PropertyBindingInitialization of BindingPropertyList with arguments value and environment.
  2. Return the result of performing RestBindingInitialization of BindingRestProperty with arguments value, environment, and excludedNames.

8.5.2.1 InitializeBoundName ( name, value, environment )

The abstract operation InitializeBoundName takes arguments name, value, and environment. It performs the following steps when called:

  1. Assert: Type(name) is String.
  2. If environment is not undefined, then
    1. Perform environment.InitializeBinding(name, value).
    2. Return NormalCompletion(undefined).
  3. Else,
    1. Let lhs be ResolveBinding(name).
    2. Return ? PutValue(lhs, value).

8.5.3 Runtime Semantics: IteratorBindingInitialization

With parameters iteratorRecord and environment.

Note

When undefined is passed for environment it indicates that a PutValue operation should be used to assign the initialization value. This is the case for formal parameter lists of non-strict functions. In that case the formal parameter bindings are preinitialized in order to deal with the possibility of multiple parameters with the same name.

 ArrayBindingPattern : [ ]
  1. Return NormalCompletion(empty).
 ArrayBindingPattern : [ Elision ]
  1. Return the result of performing IteratorDestructuringAssignmentEvaluation of Elision with iteratorRecord as the argument.
 ArrayBindingPattern : [ Elisionopt BindingRestElement ]
  1. If Elision is present, then
    1. Perform ? IteratorDestructuringAssignmentEvaluation of Elision with iteratorRecord as the argument.
  2. Return the result of performing IteratorBindingInitialization for BindingRestElement with iteratorRecord and environment as arguments.
 ArrayBindingPattern : [ BindingElementList , Elision ]
  1. Perform ? IteratorBindingInitialization for BindingElementList with iteratorRecord and environment as arguments.
  2. Return the result of performing IteratorDestructuringAssignmentEvaluation of Elision with iteratorRecord as the argument.
 ArrayBindingPattern : [ BindingElementList , Elisionopt BindingRestElement ]
  1. Perform ? IteratorBindingInitialization for BindingElementList with iteratorRecord and environment as arguments.
  2. If Elision is present, then
    1. Perform ? IteratorDestructuringAssignmentEvaluation of Elision with iteratorRecord as the argument.
  3. Return the result of performing IteratorBindingInitialization for BindingRestElement with iteratorRecord and environment as arguments.
 BindingElementList : BindingElementList , BindingElisionElement
  1. Perform ? IteratorBindingInitialization for BindingElementList with iteratorRecord and environment as arguments.
  2. Return the result of performing IteratorBindingInitialization for BindingElisionElement using iteratorRecord and environment as arguments.
 BindingElisionElement : Elision BindingElement
  1. Perform ? IteratorDestructuringAssignmentEvaluation of Elision with iteratorRecord as the argument.
  2. Return the result of performing IteratorBindingInitialization of BindingElement with iteratorRecord and environment as the arguments.
 SingleNameBinding : BindingIdentifier Initializeropt
  1. Let bindingId be StringValue of BindingIdentifier.
  2. Let lhs be ? ResolveBinding(bindingId, environment).
  3. If iteratorRecord.[[Done]] is false, then
    1. Let next be IteratorStep(iteratorRecord).
    2. If next is an abrupt completion, set iteratorRecord.[[Done]] to true.
    3. ReturnIfAbrupt(next).
    4. If next is false, set iteratorRecord.[[Done]] to true.
    5. Else,
      1. Let v be IteratorValue(next).
      2. If v is an abrupt completion, set iteratorRecord.[[Done]] to true.
      3. ReturnIfAbrupt(v).
  4. If iteratorRecord.[[Done]] is true, let v be undefined.
  5. If Initializer is present and v is undefined, then
    1. If IsAnonymousFunctionDefinition(Initializer) is true, then
      1. Set v to the result of performing NamedEvaluation for Initializer with argument bindingId.
    2. Else,
      1. Let defaultValue be the result of evaluating Initializer.
      2. Set v to ? GetValue(defaultValue).
  6. If environment is undefined, return ? PutValue(lhs, v).
  7. Return InitializeReferencedBinding(lhs, v).
 BindingElement : BindingPattern Initializeropt
  1. If iteratorRecord.[[Done]] is false, then
    1. Let next be IteratorStep(iteratorRecord).
    2. If next is an abrupt completion, set iteratorRecord.[[Done]] to true.
    3. ReturnIfAbrupt(next).
    4. If next is false, set iteratorRecord.[[Done]] to true.
    5. Else,
      1. Let v be IteratorValue(next).
      2. If v is an abrupt completion, set iteratorRecord.[[Done]] to true.
      3. ReturnIfAbrupt(v).
  2. If iteratorRecord.[[Done]] is true, let v be undefined.
  3. If Initializer is present and v is undefined, then
    1. Let defaultValue be the result of evaluating Initializer.
    2. Set v to ? GetValue(defaultValue).
  4. Return the result of performing BindingInitialization of BindingPattern with v and environment as the arguments.
 BindingRestElement : ... BindingIdentifier
  1. Let lhs be ? ResolveBinding(StringValue of BindingIdentifier, environment).
  2. Let A be ! ArrayCreate(0).
  3. Let n be 0.
  4. Repeat,
    1. If iteratorRecord.[[Done]] is false, then
      1. Let next be IteratorStep(iteratorRecord).
      2. If next is an abrupt completion, set iteratorRecord.[[Done]] to true.
      3. ReturnIfAbrupt(next).
      4. If next is false, set iteratorRecord.[[Done]] to true.
    2. If iteratorRecord.[[Done]] is true, then
      1. If environment is undefined, return ? PutValue(lhs, A).
      2. Return InitializeReferencedBinding(lhs, A).
    3. Let nextValue be IteratorValue(next).
    4. If nextValue is an abrupt completion, set iteratorRecord.[[Done]] to true.
    5. ReturnIfAbrupt(nextValue).
    6. Perform ! CreateDataPropertyOrThrow(A, ! ToString(𝔽(n)), nextValue).
    7. Set n to n + 1.
 BindingRestElement : ... BindingPattern
  1. Let A be ! ArrayCreate(0).
  2. Let n be 0.
  3. Repeat,
    1. If iteratorRecord.[[Done]] is false, then
      1. Let next be IteratorStep(iteratorRecord).
      2. If next is an abrupt completion, set iteratorRecord.[[Done]] to true.
      3. ReturnIfAbrupt(next).
      4. If next is false, set iteratorRecord.[[Done]] to true.
    2. If iteratorRecord.[[Done]] is true, then
      1. Return the result of performing BindingInitialization of BindingPattern with A and environment as the arguments.
    3. Let nextValue be IteratorValue(next).
    4. If nextValue is an abrupt completion, set iteratorRecord.[[Done]] to true.
    5. ReturnIfAbrupt(nextValue).
    6. Perform ! CreateDataPropertyOrThrow(A, ! ToString(𝔽(n)), nextValue).
    7. Set n to n + 1.
 FormalParameters : [empty]
  1. Return NormalCompletion(empty).
 FormalParameters : FormalParameterList , FunctionRestParameter
  1. Perform ? IteratorBindingInitialization for FormalParameterList using iteratorRecord and environment as the arguments.
  2. Return the result of performing IteratorBindingInitialization for FunctionRestParameter using iteratorRecord and environment as the arguments.
 FormalParameterList : FormalParameterList , FormalParameter
  1. Perform ? IteratorBindingInitialization for FormalParameterList using iteratorRecord and environment as the arguments.
  2. Return the result of performing IteratorBindingInitialization for FormalParameter using iteratorRecord and environment as the arguments.
 ArrowParameters : BindingIdentifier
  1. Assert: iteratorRecord.[[Done]] is false.
  2. Let next be IteratorStep(iteratorRecord).
  3. If next is an abrupt completion, set iteratorRecord.[[Done]] to true.
  4. ReturnIfAbrupt(next).
  5. If next is false, set iteratorRecord.[[Done]] to true.
  6. Else,
    1. Let v be IteratorValue(next).
    2. If v is an abrupt completion, set iteratorRecord.[[Done]] to true.
    3. ReturnIfAbrupt(v).
  7. If iteratorRecord.[[Done]] is true, let v be undefined.
  8. Return the result of performing BindingInitialization for BindingIdentifier using v and environment as the arguments.
 ArrowParameters : CoverParenthesizedExpressionAndArrowParameterList
  1. Let formals be CoveredFormalsList of CoverParenthesizedExpressionAndArrowParameterList.
  2. Return IteratorBindingInitialization of formals with arguments iteratorRecord and environment.
 AsyncArrowBindingIdentifier : BindingIdentifier
  1. Assert: iteratorRecord.[[Done]] is false.
  2. Let next be IteratorStep(iteratorRecord).
  3. If next is an abrupt completion, set iteratorRecord.[[Done]] to true.
  4. ReturnIfAbrupt(next).
  5. If next is false, set iteratorRecord.[[Done]] to true.
  6. Else,
    1. Let v be IteratorValue(next).
    2. If v is an abrupt completion, set iteratorRecord.[[Done]] to true.
    3. ReturnIfAbrupt(v).
  7. If iteratorRecord.[[Done]] is true, let v be undefined.
  8. Return the result of performing BindingInitialization for BindingIdentifier using v and environment as the arguments.

8.5.4 Static Semantics: AssignmentTargetType

IdentifierReference : Identifier
  1. If this IdentifierReference is contained in strict mode code and StringValue of Identifier is "eval" or "arguments", return invalid.
  2. Return simple.
 IdentifierReference : yield await CallExpression : CallExpression [ Expression ] CallExpression . IdentifierName MemberExpression : MemberExpression [ Expression ] MemberExpression . IdentifierName SuperProperty
  1. Return simple.
 PrimaryExpression : CoverParenthesizedExpressionAndArrowParameterList
  1. Let expr be CoveredParenthesizedExpression of CoverParenthesizedExpressionAndArrowParameterList.
  2. Return AssignmentTargetType of expr.
 PrimaryExpression : this Literal ArrayLiteral ObjectLiteral FunctionExpression ClassExpression GeneratorExpression AsyncFunctionExpression AsyncGeneratorExpression RegularExpressionLiteral TemplateLiteral CallExpression : CoverCallExpressionAndAsyncArrowHead SuperCall ImportCall CallExpression Arguments CallExpression TemplateLiteral NewExpression : new NewExpression MemberExpression : MemberExpression TemplateLiteral new MemberExpression Arguments NewTarget : new . target ImportMeta : import . meta LeftHandSideExpression : OptionalExpression UpdateExpression : LeftHandSideExpression ++ LeftHandSideExpression -- ++ UnaryExpression -- UnaryExpression UnaryExpression : delete UnaryExpression void UnaryExpression typeof UnaryExpression + UnaryExpression - UnaryExpression ~ UnaryExpression ! UnaryExpression AwaitExpression ExponentiationExpression : UpdateExpression ** ExponentiationExpression MultiplicativeExpression : MultiplicativeExpression MultiplicativeOperator ExponentiationExpression AdditiveExpression : AdditiveExpression + MultiplicativeExpression AdditiveExpression - MultiplicativeExpression ShiftExpression : ShiftExpression << AdditiveExpression ShiftExpression >> AdditiveExpression ShiftExpression >>> AdditiveExpression RelationalExpression : RelationalExpression < ShiftExpression RelationalExpression > ShiftExpression RelationalExpression <= ShiftExpression RelationalExpression >= ShiftExpression RelationalExpression instanceof ShiftExpression RelationalExpression in ShiftExpression EqualityExpression : EqualityExpression == RelationalExpression EqualityExpression != RelationalExpression EqualityExpression === RelationalExpression EqualityExpression !== RelationalExpression BitwiseANDExpression : BitwiseANDExpression & EqualityExpression BitwiseXORExpression : BitwiseXORExpression ^ BitwiseANDExpression BitwiseORExpression : BitwiseORExpression | BitwiseXORExpression LogicalANDExpression : LogicalANDExpression && BitwiseORExpression LogicalORExpression : LogicalORExpression || LogicalANDExpression CoalesceExpression : CoalesceExpressionHead ?? BitwiseORExpression ConditionalExpression : ShortCircuitExpression ? AssignmentExpression : AssignmentExpression AssignmentExpression : YieldExpression ArrowFunction AsyncArrowFunction LeftHandSideExpression = AssignmentExpression LeftHandSideExpression AssignmentOperator AssignmentExpression LeftHandSideExpression &&= AssignmentExpression LeftHandSideExpression ||= AssignmentExpression LeftHandSideExpression ??= AssignmentExpression Expression : Expression , AssignmentExpression
  1. Return invalid.

8.5.5 Static Semantics: PropName

PropertyDefinition : IdentifierReference
  1. Return StringValue of IdentifierReference.
 PropertyDefinition : ... AssignmentExpression
  1. Return empty.
 PropertyDefinition : PropertyName : AssignmentExpression
  1. Return PropName of PropertyName.
 LiteralPropertyName : IdentifierName
  1. Return StringValue of IdentifierName.
 LiteralPropertyName : StringLiteral
  1. Return the SV of StringLiteral.
 LiteralPropertyName : NumericLiteral
  1. Let nbr be the NumericValue of NumericLiteral.
  2. Return ! ToString(nbr).
 ComputedPropertyName : [ AssignmentExpression ]
  1. Return empty.
 MethodDefinition : PropertyName ( UniqueFormalParameters ) { FunctionBody } get PropertyName ( ) { FunctionBody } set PropertyName ( PropertySetParameterList ) { FunctionBody }
  1. Return PropName of PropertyName.
 GeneratorMethod : * PropertyName ( UniqueFormalParameters ) { GeneratorBody }
  1. Return PropName of PropertyName.
 AsyncGeneratorMethod : async * PropertyName ( UniqueFormalParameters ) { AsyncGeneratorBody }
  1. Return PropName of PropertyName.
 ClassElement : ;
  1. Return empty.
 AsyncMethod : async PropertyName ( UniqueFormalParameters ) { AsyncFunctionBody }
  1. Return PropName of PropertyName.