@meanie/angular-duplicate-requests-filter/release/angular-duplicate-requests-filter.js

A decorator for the Angular $http service to filter duplicate requests

/**
 * @meanie/angular-duplicate-requests-filter * https://github.com/meanie/angular-duplicate-requests-filter
 *
 * Copyright (c) 2020 Adam Reis <adam@reis.nz>
 * License: MIT
 */
var _typeof = typeof Symbol === "function" && typeof Symbol.iterator === "symbol" ? function (obj) { return typeof obj; } : function (obj) { return obj && typeof Symbol === "function" && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj; };

(function (window, angular, undefined) {
  'use strict';

  /**
   * Module definition and dependencies
   */

  angular.module('DuplicateRequestsFilter.Decorator', [])

  /**
   * Config
   */
  .config(['$provide', function ($provide) {

    /**
     * Decorator for the $http service
     */
    $provide.decorator('$http', ['$delegate', '$q', function ($delegate, $q) {

      //Pending requests and local $http let for natural reference
      var pendingRequests = {};
      var $http = $delegate;

      /**
       * Hash generator
       */
      function hash(str) {
        var h = 0;
        var strlen = str.length;
        if (strlen === 0) {
          return h;
        }
        for (var i = 0, n; i < strlen; ++i) {
          n = str.charCodeAt(i);
          h = (h << 5) - h + n;
          h = h & h;
        }
        return h >>> 0;
      }

      /**
       * Helper to generate a unique identifier for a request
       */
      function getRequestIdentifier(config) {
        var str = config.method + config.url;
        if (config.params && _typeof(config.params) === 'object') {
          str += angular.toJson(config.params);
        }
        if (config.data && _typeof(config.data) === 'object') {
          str += angular.toJson(config.data);
        }
        return hash(str);
      }

      /**
       * Modified $http service
       */
      function $duplicateRequestsFilter(config) {

        //Ignore for this request?
        if (config.ignoreDuplicateRequest) {
          return $http(config);
        }

        //Get unique request identifier
        var identifier = getRequestIdentifier(config);

        //Check if such a request is pending already
        if (pendingRequests[identifier]) {
          if (config.rejectDuplicateRequest) {
            return $q.reject({
              data: '',
              headers: {},
              status: config.rejectDuplicateStatusCode || 400,
              config: config
            });
          }
          return pendingRequests[identifier];
        }

        //Create promise using $http and make sure it's reset when resolved
        pendingRequests[identifier] = $http(config).finally(function () {
          delete pendingRequests[identifier];
        });

        //Return promise
        return pendingRequests[identifier];
      }

      //Map rest of methods
      Object.keys($http).filter(function (key) {
        return typeof $http[key] === 'function';
      }).forEach(function (key) {
        return $duplicateRequestsFilter[key] = $http[key];
      });

      //Map defaults
      $duplicateRequestsFilter.defaults = $http.defaults;

      //Return it
      return $duplicateRequestsFilter;
    }]);
  }]);
})(window, window.angular);