metamaps--metamaps/app/assets/javascripts/lib/ajaxq.js
Devin Howard 2fd972ddce ajax queue (fixes #853) (#1037)
* jquery.ajaxq

* install jquery.ajaxq from npm

* patch ajaxq into Backbone code

* use ajaxq library with more github stars

* eslint
2017-01-22 13:50:34 -05:00

161 lines
5.4 KiB
JavaScript

// AjaxQ jQuery Plugin
// Copyright (c) 2012 Foliotek Inc.
// MIT License
// https://github.com/Foliotek/ajaxq
// Uses CommonJS, AMD or browser globals to create a jQuery plugin.
(function (factory) {
if (typeof define === 'function' && define.amd) {
// AMD. Register as an anonymous module.
define(['jquery'], factory);
} else if (typeof module === 'object' && module.exports) {
// Node/CommonJS
module.exports = factory(require('jquery'));
} else {
// Browser globals
factory(jQuery);
}
}(function ($) {
var queues = {};
var activeReqs = {};
// Register an $.ajaxq function, which follows the $.ajax interface, but allows a queue name which will force only one request per queue to fire.
// opts can be the regular $.ajax settings plainObject, or a callback returning the settings object, to be evaluated just prior to the actual call to $.ajax.
$.ajaxq = function(qname, opts) {
if (typeof opts === "undefined") {
throw ("AjaxQ: queue name is not provided");
}
// Will return a Deferred promise object extended with success/error/callback, so that this function matches the interface of $.ajax
var deferred = $.Deferred(),
promise = deferred.promise();
promise.success = promise.done;
promise.error = promise.fail;
promise.complete = promise.always;
// Check whether options are to be evaluated at call time or not.
var deferredOpts = typeof opts === 'function';
// Create a deep copy of the arguments, and enqueue this request.
var clonedOptions = !deferredOpts ? $.extend(true, {}, opts) : null;
enqueue(function() {
// Send off the ajax request now that the item has been removed from the queue
var jqXHR = $.ajax.apply(window, [deferredOpts ? opts() : clonedOptions]);
// Notify the returned deferred object with the correct context when the jqXHR is done or fails
// Note that 'always' will automatically be fired once one of these are called: http://api.jquery.com/category/deferred-object/.
jqXHR.done(function() {
deferred.resolve.apply(this, arguments);
});
jqXHR.fail(function() {
deferred.reject.apply(this, arguments);
});
jqXHR.always(dequeue); // make sure to dequeue the next request AFTER the done and fail callbacks are fired
return jqXHR;
});
return promise;
// If there is no queue, create an empty one and instantly process this item.
// Otherwise, just add this item onto it for later processing.
function enqueue(cb) {
if (!queues[qname]) {
queues[qname] = [];
var xhr = cb();
activeReqs[qname] = xhr;
}
else {
queues[qname].push(cb);
}
}
// Remove the next callback from the queue and fire it off.
// If the queue was empty (this was the last item), delete it from memory so the next one can be instantly processed.
function dequeue() {
if (!queues[qname]) {
return;
}
var nextCallback = queues[qname].shift();
if (nextCallback) {
var xhr = nextCallback();
activeReqs[qname] = xhr;
}
else {
delete queues[qname];
delete activeReqs[qname];
}
}
};
// Register a $.postq and $.getq method to provide shortcuts for $.get and $.post
// Copied from jQuery source to make sure the functions share the same defaults as $.get and $.post.
$.each( [ "getq", "postq" ], function( i, method ) {
$[ method ] = function( qname, url, data, callback, type ) {
if ( $.isFunction( data ) ) {
type = type || callback;
callback = data;
data = undefined;
}
return $.ajaxq(qname, {
type: method === "postq" ? "post" : "get",
url: url,
data: data,
success: callback,
dataType: type
});
};
});
var isQueueRunning = function(qname) {
return (queues.hasOwnProperty(qname) && queues[qname].length > 0) || activeReqs.hasOwnProperty(qname);
};
var isAnyQueueRunning = function() {
for (var i in queues) {
if (isQueueRunning(i)) return true;
}
return false;
};
$.ajaxq.isRunning = function(qname) {
if (qname) return isQueueRunning(qname);
else return isAnyQueueRunning();
};
$.ajaxq.getActiveRequest = function(qname) {
if (!qname) throw ("AjaxQ: queue name is required");
return activeReqs[qname];
};
$.ajaxq.abort = function(qname) {
if (!qname) throw ("AjaxQ: queue name is required");
var current = $.ajaxq.getActiveRequest(qname);
delete queues[qname];
delete activeReqs[qname];
if (current) current.abort();
};
$.ajaxq.clear = function(qname) {
if (!qname) {
for (var i in queues) {
if (queues.hasOwnProperty(i)) {
queues[i] = [];
}
}
}
else {
if (queues[qname]) {
queues[qname] = [];
}
}
};
}));