> For the complete documentation index, see [llms.txt](https://strctr.gitbook.io/programming/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://strctr.gitbook.io/programming/01-languages/javascript/01-language/e-controls/e3-generators/09-generator-lazy.md).

# 09. Lazy sequences

```javascript
function* objectEntries(obj) {
  const propKeys = Reflect.ownKeys(obj);

  for (const propKey of propKeys) {
    // `yield` returns a value and then pauses
    // the generator. Later, execution continues
    // where it was previously paused.
    yield [propKey, obj[propKey]];
  }
}

const jane = { first: "Jane", last: "Doe" };
for (const [key, value] of objectEntries(jane)) {
  console.log(`${key}: ${value}`);
}
```