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Promise "loop" using the Bluebird library
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| var Promise = require('bluebird'); | |
| var promiseWhile = function(condition, body) { | |
| var resolver = Promise.defer(); | |
| var loop = function() { | |
| if (!condition()) return resolver.resolve(); | |
| return Promise.cast(body()) | |
| .then(loop) | |
| .catch(resolver.reject); | |
| }; | |
| process.nextTick(loop); | |
| return resolver.promise; | |
| }; |
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| // Assuming the above gist and the Bluebird library have been included already of course... | |
| var sum = 0, | |
| stop = 10; | |
| promiseWhile(function() { | |
| // Condition for stopping | |
| return sum < stop; | |
| }, function() { | |
| // The function to run, should return a promise | |
| return new Promise(function(resolve, reject) { | |
| // Arbitrary 25ms async method to simulate async process | |
| setTimeout(function() { | |
| sum++; | |
| // Print out the sum thus far to show progress | |
| console.log(sum); | |
| resolve(); | |
| }, 250); | |
| }); | |
| }).then(function() { | |
| // Notice we can chain it because it's a Promise, this will run after completion of the promiseWhile Promise! | |
| console.log("Done"); | |
| }); |
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