Error: Attempting to access property 'post' of an undefined variable is not possible

Question

Error: Attempting to access property 'post' of an undefined variable is not possible

Encountering an Error:

TypeError: Cannot read property 'post' of undefined
    at postName (http://127.0.0.1:9000/scripts/controllers/main.js:28:12)
    at Scope.$scope.submit (http://127.0.0.1:9000/scripts/controllers/main.js:10:7)
    at http://127.0.0.1:9000/bower_components/angular/angular.js:10348:21
    at http://127.0.0.1:9000/bower_components/angular/angular.js:18333:17
    at Scope.$eval (http://127.0.0.1:9000/bower_components/angular/angular.js:12175:28)
    at Scope.$apply (http://127.0.0.1:9000/bower_components/angular/angular.js:12273:23)
    at Scope.$delegate.__proto__.$apply (<anonymous>:855:30)
    at HTMLFormElement.<anonymous> (http://127.0.0.1:9000/bower_components/angular/angular.js:18332:21)
    at HTMLFormElement.jQuery.event.dispatch (http://127.0.0.1:9000/bower_components/jquery/dist/jquery.js:4641:9)
    at HTMLFormElement.elemData.handle (http://127.0.0.1:9000/bower_components/jquery/dist/jquery.js:4309:46) angular.js:9563(anonymous function) angular.js:9563(anonymous function) angular.js:7004Scope.$apply angular.js:12275$delegate.__proto__.$apply VM1976:855(anonymous function) angular.js:18332jQuery.event.dispatch jquery.js:4641elemData.handle

The content of my main.js file:

'use strict';

angular.module('sayHiApp')
  .controller('MainCtrl', function ($scope) {

    // Takes form input
    $scope.submit = function() {

      // Sending data to webservice via POST
      postName($scope.input);

      // Retrieving data from webservice
      var name = getName();

      // DEBUG: Combining greeting message
      $scope.greeting = 'Sup ' + name + ' !';

    };

    function postName ($scope, $http, dataToPost) {

      $http.post('/name', dataToPost).
      success(function(data) {
        $scope.error = false;
        $scope.data = data;
      }).
      error(function(data) {
        $scope.error = true;
        $scope.data = data;
      });
    }

    // Fetching name from webservice
    function getName ($scope, $http) {

      $http.get('/name').
      success(function(data) {
        $scope.error = false;
        $scope.data = data;

        return data;
      }).
      error(function(data) {
        $scope.error = true;
        $scope.data = data;

        return 'error name';
      });

    }

  });

I am confused about the root cause of this error. If it pertains to the 'post' method on '$http', I would appreciate any clarification.. Thank you in advance for your assistance :)

javascript angularjs

Answer 1

Answer №1

Here, we are discussing the use of the 'post' method in relation to '$http'.

In order for angular to inject $http into the controller function, you must add it as a parameter (similar to how you did with $scope).

I made a modification to your code by removing the $scope and $http parameters from the inner functions since they are already accessible due to closure.

angular.module('sayHiApp')
  .controller('MainCtrl', function ($scope, $http) {

// Accepts form input
$scope.submit = function() {

  // Sends data via POST request to webservice
  postName($scope.input);

  // Retrieves data from webservice
  var name = getName();

  // DEBUG: Creates greeting message
  $scope.greeting = 'Sup ' + name + ' !';

};

function postName (dataToPost) {

  $http.post('/name', dataToPost).
  success(function(data) {
    $scope.error = false;
    $scope.data = data;
  }).
  error(function(data) {
    $scope.error = true;
    $scope.data = data;
  });
}

// Retrieves name from webservice
function getName () {

  $http.get('/name').
  success(function(data) {
    $scope.error = false;
    $scope.data = data;

    return data;
  }).
  error(function(data) {
    $scope.error = true;
    $scope.data = data;

    return 'error name';
  });
}
});

Answer 2

Here, we are discussing the use of the 'post' method in relation to '$http'.

In order for angular to inject $http into the controller function, you must add it as a parameter (similar to how you did with $scope).

I made a modification to your code by removing the $scope and $http parameters from the inner functions since they are already accessible due to closure.

angular.module('sayHiApp')
  .controller('MainCtrl', function ($scope, $http) {

// Accepts form input
$scope.submit = function() {

  // Sends data via POST request to webservice
  postName($scope.input);

  // Retrieves data from webservice
  var name = getName();

  // DEBUG: Creates greeting message
  $scope.greeting = 'Sup ' + name + ' !';

};

function postName (dataToPost) {

  $http.post('/name', dataToPost).
  success(function(data) {
    $scope.error = false;
    $scope.data = data;
  }).
  error(function(data) {
    $scope.error = true;
    $scope.data = data;
  });
}

// Retrieves name from webservice
function getName () {

  $http.get('/name').
  success(function(data) {
    $scope.error = false;
    $scope.data = data;

    return data;
  }).
  error(function(data) {
    $scope.error = true;
    $scope.data = data;

    return 'error name';
  });
}
});

Answer 3

Answer №2

In order to simplify the code, the postName function does not require the variables $scope and $http to be passed as arguments. All that is needed is the dataToPost. The function can be written as follows:

function postName(dataToPost) {

  $http.post('/name', dataToPost).
  success(function(data) {
    $scope.error = false;
    $scope.data = data;
  }).
  error(function(data) {
    $scope.error = true;
    $scope.data = data;
  });
}

Answer 4

In order to simplify the code, the postName function does not require the variables $scope and $http to be passed as arguments. All that is needed is the dataToPost. The function can be written as follows:

function postName(dataToPost) {

  $http.post('/name', dataToPost).
  success(function(data) {
    $scope.error = false;
    $scope.data = data;
  }).
  error(function(data) {
    $scope.error = true;
    $scope.data = data;
  });
}

Error: Attempting to access property 'post' of an undefined variable is not possible

Answer №1

Answer №2

Similar questions

How can I apply a jquery method to a variable when JavaScript already has a method with the same name?

Add values to each entry in a subarray

How can I make sure my rows are properly aligned using the Grid

What strategies are typically employed to prevent falling into the callback hell trap when working with error-back asynchronous functions in Node.JS?

Sending a massive video file to a node.js server and saving it in AWS S3 with ReactJS

Introducing a new feature in React-Select: enabling copy-paste functionality for the multi-select text

Issue with react-table: data not displayed upon initial load and after refreshing the page

Issue with scrolling in Droppable container on JQuery UI interface

Is it advantageous to have multiple AngularJS applications for a single website?

Connect the CSS active state to a JavaScript event

Scroll upwards within a nested div

Guide to setting up ajax to parse the text input and generate a table

Absence of Callback Function Detected

Exploring the Bounds of Mongodb's $within Query

Handling onclick events in Scrapy Splash: A comprehensive guide

Invoke the parent method within the child application

Iterate through each checkbox within a specific classed div to check for selected options

Formatting Strings in JavaScript when saving as a .txt file with proper indentation

"Developing an Ionic app that utilizes Angular to send POST requests to a socket

Use Material UI TextField to prompt an email client or make a phone call