Function has

src/index.ts:147–151

(prefix: ParseYieldable)

}

export function has(prefix: ParseYieldable): () => ParseGenerator<boolean> {
  return function* () {
    return (yield [prefix, '']) !== '';
  };
}

export function optional(...potentials: Array<ParseYieldable | any>): () => ParseGenerator<any> {
  return function* () {