Easily wait until all deferreds (implementing 'then') have been resolved. Accepts two arguments, an array of deferreds (must have a 'then' method accepting a callback) and a master callback, that is fired when all deferreds have been resolved. Each deferred's resolved value(s) are then passed as argument objects to the callback. This is best used with a modified version of [nano-q](nano-q, https://gist.github.com/1129049), which allows for an arbitrary number of values to be passed into the 'resolve' method. This works with the original nano-q as well.
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when: Easily fire a callback when all deferreds are complete
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| function( | |
| a, // array of deferreds (each implements "then") | |
| b, // on complete callback | |
| c // placeholder for finished deferred count | |
| ){ | |
| c = 0, // initialize complete counter | |
| a.forEach( function(d, e, f){ // for each deferred | |
| d.then( function(){ // attach a "then" callback | |
| f[e] = arguments, // that puts the passed args in to an ordered array | |
| ++c == a.length // mark that this deferred is resolved | |
| && // if all deferreds have resolved... | |
| b.apply({}, a) // ...fire callback, using {} as context | |
| } ) | |
| }) | |
| } | |
| // this version is longer (still under 140!), | |
| // but can be used in envs without Array.forEach | |
| function( | |
| a, // array of deferreds (each implements "then") | |
| b, // on complete callback | |
| c, // placeholder | |
| d, // placeholder | |
| e // placeholder | |
| ){ | |
| for( // loop through all deferreds, in reverse order | |
| c = d = a.length, // keep length for later | |
| e = 0; // initialize complete counter | |
| d--; // loop until zero | |
| ) | |
| a[d] // grab deferred, | |
| .then( function(i){ // set callback to returned fn, | |
| return function(){ // capturing the deferred's arg position (d) | |
| a[i] = arguments, // save callback args, preserving order | |
| ++e == c // mark that this deferred is resolved | |
| && // if all deferreds have resolved... | |
| b.apply({}, a) // ...fire callback, using {} as context | |
| } | |
| }(d) ) | |
| } |
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| function(a,b,c){c=0,a.forEach(function(d,e,f){d.then(function(){f[e]=arguments,++c==a.length&&b.apply({},a)})})} |
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| DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE | |
| Version 2, December 2004 | |
| Copyright (C) 2011 Andrew Petersen <http://kirbysayshi.github.com> | |
| Everyone is permitted to copy and distribute verbatim or modified | |
| copies of this license document, and changing it is allowed as long | |
| as the name is changed. | |
| DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE | |
| TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION | |
| 0. You just DO WHAT THE FUCK YOU WANT TO. |
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| { | |
| "name": "when", | |
| "description": "A jQuery-like 'when' (or 'join') for nano-q, (https://gist.github.com/1129049).", | |
| "keywords": [ | |
| "deferred", | |
| "defer", | |
| "when", | |
| "utility" | |
| ] | |
| } |
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| <!DOCTYPE html> | |
| <title>When, for deferreds</title> | |
| <div>Expected value: <br/><b>what when how</b><br /><b>what when how</b></div> | |
| <div>Actual value: <b id="ret"></b></div> | |
| <script> | |
| // modified nano-q, allows for multiple args to resolve(): https://gist.github.com/1129049 | |
| var dfd = function(a,b){a=[];return{resolve:function(){b=arguments;while(a.length)a.shift().apply({},b);a=0},then:function(c){a?a.push(c):c.apply({},b)}}} | |
| // this is the "official" version, but requires Array.prototype.forEach | |
| var when = function(a,b,c){c=0,a.forEach(function(d,e,f){d.then(function(){f[e]=arguments,++c==a.length&&b.apply({},a)})})} | |
| // this does not require Array.prototype.forEach | |
| var whenNoES5 = function(a,b,c,d,e){for(c=d=a.length,e=0;d--;)a[d].then(function(d){return function(){a[d]=arguments,++e==c&&b.apply({},a)}}(d))} | |
| var a = dfd(), b = dfd(), c = dfd() | |
| whenNoES5( [a, b, c], function(a, b, c){ | |
| document.getElementById( "ret" ).innerHTML += | |
| '<br />' + a[1] + b[1] + c[1] | |
| }); | |
| when( [a, b, c], function(a, b, c){ | |
| document.getElementById( "ret" ).innerHTML += | |
| '<br />' + a[1] + b[1] + c[1] | |
| }); | |
| a.resolve( new Error(), 'what ' ) | |
| b.resolve( null, 'when ' ) | |
| c.resolve( null, 'how' ) | |
| </script> |
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