HTML:
<!DOCTYPE html>
<html lang="en">
<head>
<script type="text/javascript" src="/jquery-2.1.4.js"></script>
<script type="text/javascript" src="/index.js" defer></script>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<div id="withoutPromise">
<b>Example without promise:<p/></b>
</div>
<div id="withJqueryPromise">
<b>Example with jQuery promise:<p/></b>
</div>
<div id="pureJavaScriptPromiseWithoutJquery">
<b>Example with pure JavaScript promise (without jQuery):<p/></b>
</div>
</body>
</html>
JS:
/*global console, $, XMLHttpRequest*/
(function () {
"use strict";
function fillResult(id, data) {
$.each(data, function (key, val) {
$(id).append("key: " + key + "<br/>value: " + val + "<p/>");
});
}
function fillPromiseResult(data) {
$.each(JSON.parse(data), function (key, val) {
$('#pureJavaScriptPromiseWithoutJquery').append("key: " + key + "<br/>value: " + val + "<p/>");
});
}
$.getJSON("index.json", function (data) {
fillResult("#withoutPromise", data);
});
$.getJSON("index.json").done(function (data) {
fillResult("#withJqueryPromise", data);
});
function makeRequest() {
return new Promise(function (resolve, reject) {
var myJson = new XMLHttpRequest();
myJson.open("GET", "http://localhost:63342/promiseExample/index.json");
myJson.onload = function () {
if (this.status >= 200 && this.status < 300) {
resolve(myJson.response);
} else {
reject(this.statusText);
}
};
myJson.send();
});
}
makeRequest().then(fillPromiseResult, function (errorMsg) {
$("#pureJavaScriptPromiseWithoutJquery").append(errorMsg);
}).catch(function (err) {
console.log("Error: " + err);
});
}());
JSON:
{
"first": "first test",
"second": "second test",
"nested test": [
{"first nest": "nest one"},
{"second nest": "nest two"}
]
}
Mostly I was using this example. Notice that it seems that resolve method of promise can accept only one parameter, that is why I needed to create function special for promise. Example download from here.