15 lines
572 B
Markdown
15 lines
572 B
Markdown
### Promisify
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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)
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```js
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const promisify = func =>
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(...args) =>
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new Promise((resolve, reject) =>
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func(...args, (err, result) =>
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err ? reject(err) : resolve(result))
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);
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// const delay = promisify((d, cb) => setTimeout(cb, d))
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// delay(2000).then(() => console.log('Hi!')) -> Promise resolves after 2s
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```
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