An object is not defined in the following scenario

Question

An object is not defined in the following scenario

I currently have a custom function that includes the following code snippet:

1:  var object = get_resource($scope, CbgenRestangular, $stateParams.scheme_id);
2:  console.log(object)

This function triggers the following code:

get_resource = function ($scope, CbgenRestangular, id){
    CbgenRestangular.one('scheme', id).get().then(function(object){
             console.log(object)
        return object
    })
},

My problem arises when the console.log within the get_resource function correctly outputs the object, but on line 2 in the main code snippet it shows as undefined. Why is this happening?

The object should be the same throughout the entire process, so why does it appear as undefined when I try to return it?

javascript angularjs

Answer 1

Answer №1

The issue with the get_resource function is that it lacks a return statement, resulting in an output of undefined. Even though there is a return statement within the function passed to the then function, it does not exit the "outer" function.

What you are actually working with here are promises. The get function seems to be returning a promise:

var promise = CbgenRestangular.one('scheme', id).get();

To obtain the result of this promise, you will need to utilize the then function, just like how it was done within the get_resource function.

If you wish to handle this promise outside of the current function, you can simply return the promise and proceed with the same steps:

get_resource = function ($scope, CbgenRestangular, id){
    return CbgenRestangular.one('scheme', id).get().then(function(object){
             console.log(object)
        return object
    })
}, 

//.....

var promise = get_resource($scope, CbgenRestangular, $stateParams.scheme_id);
promise.then(function (object) {
    console.log(object);
});

Answer 2

The issue with the get_resource function is that it lacks a return statement, resulting in an output of undefined. Even though there is a return statement within the function passed to the then function, it does not exit the "outer" function.

What you are actually working with here are promises. The get function seems to be returning a promise:

var promise = CbgenRestangular.one('scheme', id).get();

To obtain the result of this promise, you will need to utilize the then function, just like how it was done within the get_resource function.

If you wish to handle this promise outside of the current function, you can simply return the promise and proceed with the same steps:

get_resource = function ($scope, CbgenRestangular, id){
    return CbgenRestangular.one('scheme', id).get().then(function(object){
             console.log(object)
        return object
    })
}, 

//.....

var promise = get_resource($scope, CbgenRestangular, $stateParams.scheme_id);
promise.then(function (object) {
    console.log(object);
});

Answer 3

Answer №2

JavaScript operates asychronously, a key concept to grasp in programming. When calling a function that involves an ajax request (a lengthy operation), the use of a callback is necessary.

Your code may fail due to a scenario where one function calls another which then returns an object. However, the first function does not recognize this and ends up returning undefined immediately.

To resolve this issue, consider implementing the following:

fetchResource = function ($scope, CbgenRestangular, id, _callback){
   CbgenRestangular.one('scheme', id).get().then(function(obj){
      _callback(obj);
 })
},

fetchResource($scope, CbgenRestangular, $stateParams.scheme_id,function(_obj){
  console.log(_obj)
});

Additionally, avoid naming variables "object" as this term is reserved for other purposes.

Answer 4

JavaScript operates asychronously, a key concept to grasp in programming. When calling a function that involves an ajax request (a lengthy operation), the use of a callback is necessary.

Your code may fail due to a scenario where one function calls another which then returns an object. However, the first function does not recognize this and ends up returning undefined immediately.

To resolve this issue, consider implementing the following:

fetchResource = function ($scope, CbgenRestangular, id, _callback){
   CbgenRestangular.one('scheme', id).get().then(function(obj){
      _callback(obj);
 })
},

fetchResource($scope, CbgenRestangular, $stateParams.scheme_id,function(_obj){
  console.log(_obj)
});

Additionally, avoid naming variables "object" as this term is reserved for other purposes.

An object is not defined in the following scenario

Answer №1

Answer №2

Similar questions

ng-click event triggers twice in directive-driven navigation

Utilize JavaScript to extract content from a text file and showcase it in a Bootstrap modal pop-up through knockout binding

Unable to reinitialize MUI DatePicker after keydown event

Experiencing difficulties integrating relational data with Angular and MongoDB

The callback for AJAX was unsuccessful

Create a loop in Vue.js 3 without the need for a query

Firing a custom jQuery event when a page loaded via AJAX is complete, ensuring it is triggered

Using Alpine JS to rotate through images at regular intervals using the window.setInterval() method

What is the process for creating the AngularJS documentation?

Converting a PHP string into a JSON array

Adjust SVG size as per parent container in AngularJS custom directive

Issue with VueJS where the data list cannot be accessed from one template in another template

Using an array of JSON objects to set up a Backbone.js bootstrap-initialized application

Is there a way to fetch and display property changes in Vue Material's md-dialog?

Angular's ng-class directive functions correctly with an input element of type "text", but it does not

Typescript is throwing a Mongoose error stating that the Schema has not been registered for the model

Incorporating arguments within the context of a "for each" loop

Guide on transferring binary image data to a JavaScript function

Exploring an XML document with HTML

Creating dynamic height based on width using JavaScript