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105 lines
2.2 KiB
Markdown
105 lines
2.2 KiB
Markdown
3 weeks ago
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# Run Async
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[](http://badge.fury.io/js/run-async)
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Utility method to run a function either synchronously or asynchronously using a series of common patterns. This is useful for library author accepting sync or async functions as parameter. `runAsync` will always run them as an async method, and normalize the multiple signature.
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# Installation
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```bash
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npm install --save run-async
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```
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# Usage
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Here's a simple example print the function results and three options a user can provide a function.
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```js
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var runAsync = require("run-async");
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var printAfter = function (func) {
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var cb = function (err, returnValue) {
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console.log(returnValue);
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};
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runAsync(func, cb)(/* arguments for func */);
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};
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```
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#### Using `this.async`
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```js
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printAfter(function () {
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var done = this.async();
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setTimeout(function () {
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done(null, "done running with callback");
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}, 10);
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});
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```
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#### Returning a promise
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```js
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printAfter(function () {
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return new Promise(function (resolve, reject) {
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resolve("done running with promises");
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});
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});
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```
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#### Synchronous function
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```js
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printAfter(function () {
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return "done running sync function";
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});
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```
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#### Custom done factory
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```js
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var runAsync = require("run-async");
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runAsync(function () {
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var callback = this.customAsync();
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callback(null, a + b);
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}, "customAsync")(1, 2);
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```
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#### Passing context to async method
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```js
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var runAsync = require("run-async");
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runAsync(function () {
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assert(this.isBound);
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var callback = this.async();
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callback(null, a + b);
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}).call({ isBound: true }, 1, 2);
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```
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### runAsync.cb
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`runAsync.cb` supports all the function types that `runAsync` does and additionally a traditional **callback as the last argument** signature:
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```js
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var runAsync = require("run-async");
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// IMPORTANT: The wrapped function must have a fixed number of parameters.
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runAsync.cb(
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function (a, b, cb) {
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cb(null, a + b);
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},
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function (err, result) {
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console.log(result);
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},
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)(1, 2);
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```
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If your version of node support Promises natively (node >= 0.12), `runAsync` will return a promise. Example: `runAsync(func)(arg1, arg2).then(cb)`
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# Licence
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Copyright (c) 2014 Simon Boudrias (twitter: @vaxilart)
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Licensed under the MIT license.
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