code: function stripFlag(val, negate) {
      negate = escape(negate || constants_1.NEGATE_CHAR);
      return (val || '').replace(new RegExp('^--?(' + negate + ')?'), '');
  }
docs: Strips a flag of all tokens.
  
  @example --user.name >> user.name
  @example --no-force >> force (removes negation also)
  
  @param val the value containing flag tokens to be stripped.
  @param negate the negation char defined in options.