1 | /* JavaScript Sync/Async forEach - v0.1.2 - 1/10/2012
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2 | * http://github.com/cowboy/javascript-sync-async-foreach
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3 | * Copyright (c) 2012 "Cowboy" Ben Alman; Licensed MIT */
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4 |
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5 | (function(exports) {
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6 |
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7 | // Iterate synchronously or asynchronously.
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8 | exports.forEach = function(arr, eachFn, doneFn) {
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9 | var i = -1;
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10 | // Resolve array length to a valid (ToUint32) number.
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11 | var len = arr.length >>> 0;
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12 |
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13 | // This IIFE is called once now, and then again, by name, for each loop
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14 | // iteration.
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15 | (function next(result) {
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16 | // This flag will be set to true if `this.async` is called inside the
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17 | // eachFn` callback.
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18 | var async;
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19 | // Was false returned from the `eachFn` callback or passed to the
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20 | // `this.async` done function?
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21 | var abort = result === false;
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22 |
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23 | // Increment counter variable and skip any indices that don't exist. This
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24 | // allows sparse arrays to be iterated.
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25 | do { ++i; } while (!(i in arr) && i !== len);
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26 |
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27 | // Exit if result passed to `this.async` done function or returned from
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28 | // the `eachFn` callback was false, or when done iterating.
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29 | if (abort || i === len) {
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30 | // If a `doneFn` callback was specified, invoke that now. Pass in a
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31 | // boolean value representing "not aborted" state along with the array.
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32 | if (doneFn) {
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33 | doneFn(!abort, arr);
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34 | }
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35 | return;
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36 | }
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37 |
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38 | // Invoke the `eachFn` callback, setting `this` inside the callback to a
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39 | // custom object that contains one method, and passing in the array item,
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40 | // index, and the array.
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41 | result = eachFn.call({
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42 | // If `this.async` is called inside the `eachFn` callback, set the async
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43 | // flag and return a function that can be used to continue iterating.
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44 | async: function() {
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45 | async = true;
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46 | return next;
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47 | }
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48 | }, arr[i], i, arr);
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49 |
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50 | // If the async flag wasn't set, continue by calling `next` synchronously,
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51 | // passing in the result of the `eachFn` callback.
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52 | if (!async) {
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53 | next(result);
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54 | }
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55 | }());
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56 | };
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57 |
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58 | }(typeof exports === "object" && exports || this)); |
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