Created
November 25, 2015 11:03
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03 Promisifying XMLHttpRequest
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function get(url) { | |
// Return a new promise. | |
return new Promise(function(resolve, reject) { | |
// Do the usual XHR stuff | |
var req = new XMLHttpRequest(); | |
req.open('GET', url); | |
req.onload = function() { | |
// This is called even on 404 etc | |
// so check the status | |
if (req.status == 200) { | |
// Resolve the promise with the response text | |
resolve(req.response); | |
} | |
else { | |
// Otherwise reject with the status text | |
// which will hopefully be a meaningful error | |
reject(Error(req.statusText)); | |
} | |
}; | |
// Handle network errors | |
req.onerror = function() { | |
reject(Error("Network Error")); | |
}; | |
// Make the request | |
req.send(); | |
}); | |
} | |
// Now let's use it | |
get('story.json').then(function(response) { | |
console.log("Success!", response); | |
}, function(error) { | |
console.error("Failed!", error); | |
}); |
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