You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
90 lines
2.1 KiB
90 lines
2.1 KiB
# p-locate [](https://travis-ci.org/sindresorhus/p-locate) |
|
|
|
> Get the first fulfilled promise that satisfies the provided testing function |
|
|
|
Think of it like an async version of [`Array#find`](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Array/find). |
|
|
|
|
|
## Install |
|
|
|
``` |
|
$ npm install p-locate |
|
``` |
|
|
|
|
|
## Usage |
|
|
|
Here we find the first file that exists on disk, in array order. |
|
|
|
```js |
|
const pathExists = require('path-exists'); |
|
const pLocate = require('p-locate'); |
|
|
|
const files = [ |
|
'unicorn.png', |
|
'rainbow.png', // Only this one actually exists on disk |
|
'pony.png' |
|
]; |
|
|
|
(async () => { |
|
const foundPath = await pLocate(files, file => pathExists(file)); |
|
|
|
console.log(foundPath); |
|
//=> 'rainbow' |
|
})(); |
|
``` |
|
|
|
*The above is just an example. Use [`locate-path`](https://github.com/sindresorhus/locate-path) if you need this.* |
|
|
|
|
|
## API |
|
|
|
### pLocate(input, tester, [options]) |
|
|
|
Returns a `Promise` that is fulfilled when `tester` resolves to `true` or the iterable is done, or rejects if any of the promises reject. The fulfilled value is the current iterable value or `undefined` if `tester` never resolved to `true`. |
|
|
|
#### input |
|
|
|
Type: `Iterable<Promise | unknown>` |
|
|
|
An iterable of promises/values to test. |
|
|
|
#### tester(element) |
|
|
|
Type: `Function` |
|
|
|
This function will receive resolved values from `input` and is expected to return a `Promise<boolean>` or `boolean`. |
|
|
|
#### options |
|
|
|
Type: `Object` |
|
|
|
##### concurrency |
|
|
|
Type: `number`<br> |
|
Default: `Infinity`<br> |
|
Minimum: `1` |
|
|
|
Number of concurrently pending promises returned by `tester`. |
|
|
|
##### preserveOrder |
|
|
|
Type: `boolean`<br> |
|
Default: `true` |
|
|
|
Preserve `input` order when searching. |
|
|
|
Disable this to improve performance if you don't care about the order. |
|
|
|
|
|
## Related |
|
|
|
- [p-map](https://github.com/sindresorhus/p-map) - Map over promises concurrently |
|
- [p-filter](https://github.com/sindresorhus/p-filter) - Filter promises concurrently |
|
- [p-any](https://github.com/sindresorhus/p-any) - Wait for any promise to be fulfilled |
|
- [More…](https://github.com/sindresorhus/promise-fun) |
|
|
|
|
|
## License |
|
|
|
MIT © [Sindre Sorhus](https://sindresorhus.com)
|
|
|