TypeScript · Middle · Question 67 of 75

How do you type a generator function?

function* ids(): Generator<number, void, unknown> {
  let i = 0;
  while (true) yield i++;
}

✓Correct answer: Generator<Yield, Return, Next> (or Iterable<T> / IterableIterator<T> for simple cases)
2Array<number>
3Generators can't be typed

Explanation

The third parameter is the type of values passed to next(...). Async generators use AsyncGenerator<...>.

Further reading

TS Handbook: More on Functions ↗

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