Angular - Prevent duplicate $http GETs from firing at the same time

ngHttpDedupe.js

$provide.decorator('$http', ['$delegate', function($delegate) {
  // Angular injects the service as $delegate
  var $http = $delegate;
  // Store promises for requests
  var pendingRequests = [];

  // Let's overwrite the get method to prevent duplicate queries
  $http.get = function (url, config) {
    config = config || {};
    // Let's make a simple key for us to reference on subsequent requests
    // NOTE - if the request has a timeout, deduping can result
    // in no one getting their response, so let's make the id unique
    var unique = (config.timeout) ? Date.now() : '';
    var id = url + JSON.stringify(config.params || {}) + unique;

    // See if there is already a promise for that particular key
    // and return it if there is
    var pendingRequest = _.find(pendingRequests, {id: id});
    if (pendingRequest) {
      return pendingRequest.promise;
    }

    // Do the request
    var promise = $http(angular.extend({}, config || {}, {
      method: 'get',
      url: url
    }));

    // Let's set pendingRequest to a new object with our new promise
    pendingRequest = {
      id: id,
      promise: promise
    };

    // Add the promise to the pending requests array
    pendingRequests.push(pendingRequest);

    promise.finally(function(){
      // Get rid of the reference when the promise is satisfied
      pendingRequests.splice(pendingRequests.indexOf(pendingRequest), 1);
    });

    return promise;
  };

  return $http;
}]);