generatorFunctionYields

Reports generator functions that do not yield values.

✅ This rule is included in the ts logical preset.

Generator functions use the function* syntax to create iterators that can produce multiple values over time. Without a yield expression, the generator will not produce any values and behaves like an empty iterator. This is likely unintentional and indicates incomplete implementation or a misunderstanding of generator functions.

Examples

❌ Incorrect

function* emptyGenerator() {
  console.log("No yield here");
}

function* generatorThatReturns() {
  return 42;
}

class Collection {
  *iterator() {
    this.process();
  }
}

✅ Correct

function* numbers() {
  yield 1;
  yield 2;
  yield 3;
}

function* range(start: number, end: number) {
  for (let i = start; i < end; i++) {
    yield i;
  }
}

class Collection {
  *iterator() {
    yield* this.items;
  }
}

Options

This rule is not configurable.

When Not To Use It

If you intentionally want to create generator functions that produce no values (empty iterators), you can disable this rule. However, in most cases, such functions should not be generators.

Further Reading

• MDN: function*
• MDN: yield
• MDN: Iterators and generators

Equivalents in Other Linters

• Biome: useYield
• Deno: require-yield
• ESLint: require-yield
• Oxlint: eslint/require-yield