Encountered an error stating ""TypeError: undefined is not an object" while attempting to test a

I'm currently troubleshooting a simple service and encountering the error mentioned above. After extensive research, I believe there is a null item in my code that I cannot locate. Any insights or suggestions would be greatly appreciated. Thank you!

Config.js

'use strict';    

angular.module('App').service('configService', function(
  $rootScope, $http) {
  var configObj = null;
  return {

    getConfig: function() {
      if (configObj != null) {
        console.log("returning cached config");
        return configObj;
      }
      else {
        $http.get('conf.json').then(function(res) {
          $http.get(res.confLocation).then(function(
            locationResponse) {
            configObj = locationResponse;
            $rootScope.configObj = configObj;
            console.log($rootScope.configObj);
            return configObj;
          });
        });
      }
    }
  };
});

ConfigTest.js

'use strict';

describe('Service: configService', function() {

  // load the controller's module
  beforeEach(module('App'));

  var configService, $httpBackend, results;
  var tstConfig = {
    "confLocation": "local-dev-conf.json"
  };
  var tstConfigObj = {
    "AWS": {
      "region": "us-east-1",
      "endpoint": "http://localhost:8133"
    }
  };

  // Initialize the controller and a mock scope
  beforeEach(inject(function(_configService_, _$httpBackend_) {
    inject(function($rootScope) {
      $rootScope.USERNAME = 'TESTER';
      $rootScope.configObj = tstConfigObj;
    });

    configService = configService;
    $httpBackend = _$httpBackend_;
    // backend definition common for all tests
    $httpBackend.expectGET('conf.json').respond(tstConfig);
    $httpBackend.expectGET('local-dev-conf.json').respond(tstConfigObj);
  }));

  it('it should do something', inject(function() {

    results = configService.getConfig().then(function() { //ERROR HERE

      // What should I be expecting to check if it's parsing the file?
      // expect(configFile).toEqual("Object{AWS: Object{region: 'us-east-1', endpoint: 'http://localhost:8133'}}")

      console.log(results);
    });
    $httpBackend.flush();
  }));

Answer №1

Your issue lies within the spec/testcase file where you are incorrectly assigning configService to configService. This results in a redundant assignment that causes confusion.

In addition, when calling the getConfig method from your it block, it is recommended to use spyOn for proper testing. However, without a spy on it and a missing return function named then, you are encountering an undefined error.

Refer to the example below for guidance:

'use strict';

describe('Service: configService', function() {

  // Load the controller's module
  beforeEach(module('App'));

  var configService, $httpBackend, results;
  var tstConfig = {
    "confLocation": "local-dev-conf.json"
  };
  var tstConfigObj = {
    "AWS": {
      "region": "us-east-1",
      "endpoint": "http://localhost:8133"
    }
  };

  // Initialize the controller and a mock scope
  beforeEach(inject(function(_configService_, _$httpBackend_) {
    inject(function($rootScope) {
      $rootScope.USERNAME = 'TESTER';
      $rootScope.configObj = tstConfigObj;
    });

    configService = _configService_;
    $httpBackend = _$httpBackend_;
    // Backend definition common for all tests
    $httpBackend.expectGET('conf.json').respond(tstConfig);
    $httpBackend.expectGET('local-dev-conf.json').respond(tstConfigObj);

    spyOn(configService, 'getConfig').and.callFake(function(){
        return{
            then: function(){
                return "something";
            }
        }
    });

  }));

    it('it should do something', inject(function() {

        results = configService.getConfig().then(function() { //ERROR HERE

          // What should I be expecting to check if it's parsing the file?
          // expect(configFile).toEqual("Object{AWS: Object{region: 'us-east-1', endpoint: 'http://localhost:8133'}}")

          console.log(results);
        });
        //$httpBackend.flush();
    }));

});

I hope this provides clarity on the matter.

Answer №2

The reason for the issue is that there is a missing return statement for the promise in the else block of the config.js file.

'use strict';    

angular.module('App').service('configService', function(
  $rootScope, $http) {
  var configObj = null;
  return {

    getConfig: function() {
      if (configObj != null) {
        console.log("returning cached config");
        return configObj;
      }
      else {
        // Ensure to include a return statement for the promise here
        return $http.get('conf.json').then(function(res) {
          $http.get(res.confLocation).then(function(
            locationResponse) {
            configObj = locationResponse;
            $rootScope.configObj = configObj;
            console.log($rootScope.configObj);
            return configObj;
          });
        });
      }
    }
  };
});

The error occurred because the promise was not being returned, causing the function to return undefined, which does not have a .then method.

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