18 lines
584 B
Markdown
18 lines
584 B
Markdown
### Promisify
|
|
|
|
Use currying to return a function returning a `Promise` that calls the original function.
|
|
Use the `...rest` operator to pass in all the parameters.
|
|
|
|
*In Node 8+, you can use [`util.promisify`](https://nodejs.org/api/util.html#util_util_promisify_original)*
|
|
|
|
```js
|
|
const promisify = func =>
|
|
(...args) =>
|
|
new Promise((resolve, reject) =>
|
|
func(...args, (err, result) =>
|
|
err ? reject(err) : resolve(result))
|
|
);
|
|
// const delay = promisify((d, cb) => setTimeout(cb, d))
|
|
// delay(2000).then(() => console.log('Hi!')) -> Promise resolves after 2s
|
|
```
|