deps/v8/src/js/regexp.js
function RegExpGetFlags() {
  if (!IS_RECEIVER(this)) {
    throw MakeTypeError(
        kRegExpNonObject, "RegExp.prototype.flags", TO_STRING(this));
  }
  var result = '';
  if (this.global) result += 'g';
  if (this.ignoreCase) result += 'i';
  if (this.multiline) result += 'm';
  if (this.unicode) result += 'u';
  if (this.sticky) result += 'y';
  return result;
}
function RegExpGetFlags() {
  if (!IS_RECEIVER(this)) {
    throw MakeTypeError(
        kRegExpNonObject, "RegExp.prototype.flags", TO_STRING(this));
  }
  var result = '';
  if (this.global) result += 'g';
  if (this.ignoreCase) result += 'i';
  if (this.multiline) result += 'm';
  if (this.unicode) result += 'u';
  if (this.sticky) result += 'y';
  return result;
}
function RegExpGetFlags ( ) { if ( ! IS_RECEIVER ( this ) ) { throw MakeTypeError ( kRegExpNonObject , "RegExp.prototype.flags" , TO_STRING ( this ) ) ; } var result = '' ; if ( this . global ) result += 'g' ; if ( this . ignoreCase ) result += 'i' ; if ( this . multiline ) result += 'm' ; if ( this . unicode ) result += 'u' ; if ( this . sticky ) result += 'y' ; return result ; }
ES6 21.2.5.3.
ES6 21 . 2 . 5 . 3 .