# JS Tip of the Day: Awaiting Non-promises

**URL:** <https://forum.kirupa.com/t/js-tip-of-the-day-awaiting-non-promises/643110>\
**Category:** web dev\
**Created:** [April 26, 2020, 1:54pm UTC](https://forum.kirupa.com/t/js-tip-of-the-day-awaiting-non-promises/643110 "2020-04-26T13:54:14Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![senocular](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/senocular/32/7217_2.png) [@senocular](https://forum.kirupa.com/u/senocular)\
**Post date:** [April 26, 2020, 1:54pm UTC](https://forum.kirupa.com/t/js-tip-of-the-day-awaiting-non-promises/643110/1 "2020-04-26T13:54:14Z")

</div>

**Awaiting Non-promises**  
Version ES2017  
Level: Intermediate

Normally, `await` is used to wait for the completion of a promise. When encountered, the current `async` function will pause its execution and only resume once the promise being awaited is fulfilled. But it’s also possible to use `await` with non-promises. In doing so, the `await` will implicitly wrap the value in a resolved promise.

```javascript
async function example () {
    await 0; // 0 treated as Promise.resolve(0)
}

```

It’s likely uncommon that you’d want to `await` a non-promise, though there may be cases where you have a value which may or may not be a promise. Instead of having to perform a check on that value to see, you can simply `await` it directly.

```javascript
async function waitFor (anyValue) {
    let result = await anyValue;
    return result;
}

waitFor(4)
    .then(value => console.log(value)); // 4
    
let promised4 = new Promise(resolve => {
    setTimeout(() => resolve(4), 500);
});
waitFor(promised4)
    .then(value => console.log(value)) // 4

```

Awaiting an arbitrary value this way can also be used to delay the execution of code. Once an `await` is reached, even if the value is already available (as a non-promise or a promise that’s already resolved), the execution of the `async` function is still paused and the rest of the call stack will run out until it picks up again.

```javascript
async function wrapWork () {
    console.log('Start work!');
    await 0;
    console.log('Work complete!');
}

wrapWork();
console.log('Doing all the work...');
/* logs:
Start work!
Doing all the work...
Work complete!
*/

```

More info:

- [async functions on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/async_function)
- [await on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/await)