String#matchAll is too restrictive in its parameter type

🔎 Search Terms

matchAll

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about RegExps and matchAll

⏯ Playground Link

https://www.typescriptlang.org/play?target=7#code/MYewdgzgLgBAtgTwMIFdojgeQEYCsCmwsAvDAN4CwAUDLTAFQDaAygnNiADYB0cAhlGAALAIKdOAXQAU0AE4BLMAHMAXDDmKlASjUBxfGHyyBIWQB4ASviUBRAB4AHe4RGzjCAHzlqdGAF9qAKpqUEgufG5OECUpRm54gHIAMxAQBN4BYTFOKURUdCw8QigtCS0AbmogA

💻 Code

const myCustomObject = {
    *[Symbol.matchAll](string: string): Generator<RegExpExecArray> {
    }
}

console.log([...'foo'.matchAll(myCustomObject)]);

🙁 Actual behavior

TS rejects this code, because myCustomObject is not an instance of RegExp.

🙂 Expected behavior

Any value matching the following type should be accepted, including myCustomObject. The other parts of the RegExp object are not used.

type MatchAllRegExpLike = {
  [Symbol.matchAll](string: string): IterableIterator<RegExpExecArray>;
  // If the object has a [Symbol.match] property that is truthy, its flags are checked. However, neither
  // must be present, and even if it is present, [Symbol.match] doesn't have to be a function.
  readonly [Symbol.match]?: any;
  readonly flags?: string;
};

Additional information about the issue

This is distinct from #47310. That issue is about string-to-regexp conversion; this is about regexp-like objects.

Bắt đầu với ví dụ TypeScript Playground được liên kết; issue không nêu tệp nào trong repository hay test nào. Truy vết khai báo được String#matchAll sử dụng và so sánh với dạng MatchAllRegExpLike được đề xuất, sau đó xác minh rằng ví dụ biên dịch được trong khi hành vi matchAll hiện có vẫn được kiểm thử.