question: private static boolean isIdentifierName ( String k ) { int n = k . length ( ) ; if ( n == 0 ) { return false ; } if ( ! Character . isJavaIdentifierStart ( k . charAt ( 0 ) ) ) { return false ; } for ( int i = 1 ; i < n ; ++ i ) { if ( ! Character . isJavaIdentifierPart ( k . charAt ( i ) ) ) { return false ; } } return true ; }
target:  An EcmaScript IdentifierName is an Identifier or reserved word. This is approximate to avoid bringing in extra dependencies.