var prohibitedKeywordRE = new RegExp('\\b' + (
  'do,if,for,let,new,try,var,case,else,with,await,break,catch,class,const,' +
  'super,throw,while,yield,delete,export,import,return,switch,default,' +
  'extends,finally,continue,debugger,function,arguments'
).split(',').join('\\b|\\b') + '\\b');