According to ECMA262 5.1 section 11.1.5 'Object Initialiser', getter and setter name is 'PropertyName'. PropertyAssignment : PropertyName : AssignmentExpression get PropertyName ( ) { FunctionBody } set PropertyName ( PropertySetParameterList ) { FunctionBody } And PropertyName contains StringLiteral and NumericLiteral. PropertyName : IdentifierName StringLiteral NumericLiteral So StringLiteral and NumericLiteral are allowed as ObjectLiteral getter / setter name. for example, var obj = { get 42() { return 42; }, get 'string'() { return 'string'; } }; is valid syntax.