whole_func_string: function isNegateFlag(val, negate) {
      negate = escape(negate || constants_1.NEGATE_CHAR);
      return (new RegExp('^--' + negate)).test(val);
  }
func_code_string: function isNegateFlag(val, negate) {
      negate = escape(negate || constants_1.NEGATE_CHAR);
      return (new RegExp('^--' + negate)).test(val);
  }
func_documentation_string: Checks if flag is that of negation.
  
  @example --no-force >> true
  @example --force >> false
  
  @param val the value to inspect.
  @param negate the negation char to check if exists.