90 lines
1.8 KiB
Markdown
90 lines
1.8 KiB
Markdown
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[](https://travis-ci.org/digitaldesignlabs/es6-promisify)
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# es6-promisify
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Converts callback-based functions to Promise-based functions.
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## Install
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Install with [npm](https://npmjs.org/package/es6-promisify)
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```bash
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npm install --save es6-promisify
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```
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## Example
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```js
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"use strict";
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// Declare variables
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const promisify = require("es6-promisify");
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const fs = require("fs");
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// Convert the stat function
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const stat = promisify(fs.stat);
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// Now usable as a promise!
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stat("example.txt").then(function (stats) {
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console.log("Got stats", stats);
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}).catch(function (err) {
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console.error("Yikes!", err);
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});
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```
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## Promisify methods
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```js
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"use strict";
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// Declare variables
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const promisify = require("es6-promisify");
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const redis = require("redis").createClient(6379, "localhost");
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// Create a promise-based version of send_command
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const client = promisify(redis.send_command, redis);
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// Send commands to redis and get a promise back
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client("ping").then(function (pong) {
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console.log("Got", pong);
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}).catch(function (err) {
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console.error("Unexpected error", err);
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}).then(function () {
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redis.quit();
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});
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```
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## Handle callback multiple arguments
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```js
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"use strict";
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// Declare functions
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function test(cb) {
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return cb(undefined, 1, 2, 3);
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}
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// Declare variables
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const promisify = require("es6-promisify");
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// Create promise-based version of test
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const single = promisify(test);
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const multi = promisify(test, {multiArgs: true});
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// Discards additional arguments
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single().then(function (result) {
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console.log(result); // 1
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});
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// Returns all arguments as an array
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multi().then(function (result) {
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console.log(result); // [1, 2, 3]
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});
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```
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### Tests
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Test with nodeunit
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```bash
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$ npm test
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```
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Published under the [MIT License](http://opensource.org/licenses/MIT).
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