135 lines
3.0 KiB
Markdown
135 lines
3.0 KiB
Markdown
forEachAsync
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===
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Analogous to `[].forEach`, but handles items asynchronously with a final callback passed to `then`.
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This is the most essential piece of the [`ArrayAsync`](https://github.com/FuturesJS/ArrayAsync) package.
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v3.x - Diet Cola Edition
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---
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As I do every few years, I decided to rewrite FuturesJS.
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This year's remake is extremely lightweight.
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Usage
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===
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It's as simple as you could guess:
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```javascript
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// waits for one request to finish before beginning the next
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forEachAsync(['dogs', 'cats', 'octocats'], function (next, element, index, array) {
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getPics(element, next);
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// then after all of the elements have been handled
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// the final callback fires to let you know it's all done
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}).then(function () {
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console.log('All requests have finished');
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});
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// where `getPics` might be an asynchronous web request such as this
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function getPics(animal, cb) {
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var flickerAPI = "http://api.flickr.com/services/feeds/photos_public.gne?jsoncallback=?";
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$.getJSON(
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flickerAPI
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, { tags: thing
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, tagmode: "any"
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, format: "json"
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, success: function (data) {
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console.log('teh animals:', data);
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}
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, complete: cb
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}
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);
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}
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```
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Browser Installation
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===
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You can install from bower:
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```bash
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bower install forEachAsync
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```
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Or download the raw file from <https://raw.github.com/FuturesJS/forEachAsync/master/forEachAsync.js>:
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```bash
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wget https://raw.github.com/FuturesJS/forEachAsync/master/forEachAsync.js
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```
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```javascript
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(function () {
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'use strict';
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var forEachAsync = window.forEachAsync
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;
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// do stuff ...
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}());
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```
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Or you can build it alongside other libraries:
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```bash
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npm install -g pakmanager
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npm install forEachAsync --save
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pakmanager -e browser build
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```
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```html
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<script src="pakmanaged.js"></script>
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```
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```javascript
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(function () {
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'use strict';
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var forEachAsync = require('forEachAsync').forEachAsync
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;
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// do stuff ...
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}());
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```
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Node Installation
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===
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```bash
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npm install --save forEachAsync@3.x
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```
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API
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===
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**`forEachAsync(array, callback[, thisArg])`**
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Parameters
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* `array` Array of elements to iterate over
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* `callback` Function to execute for each element, takes 4 arguments
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* `next` the function to call when the current element has been dealt with
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* `element` a single element of the aforementioned array
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* `index` the index of the current element
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* `array` the same array mentioned above
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* `thisArg` Object to use as `this` when executing `callback`
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**`forEachAsync#then(done)`**
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Parameters
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* `then` is in the return value of `forEachAsync` and accepts a final `done` callback.
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* `done` called after `forEachAsync` is complete, takes no arguments
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Internal API
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===
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`forEachAsync.__BREAK`
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This is used internally for the purposes of the `ArrayAsync` library.
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Please don't `break` stuff; use [`ArrayAsync`](https://github.com/FuturesJS/ArrayAsync)`.someAsync` or [`ArrayAsync`](https://github.com/FuturesJS/ArrayAsync)`.everyAsync` instead.
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