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Ember.js Promise catch() Method

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Ember.js is an open-source JavaScript framework used for developing large client-side web applications which are based on Model-View-Controller (MVC) architecture. Ember.js is one of the most widely used front-end application frameworks. It is made to speed up development and increase productivity. Currently, it is utilized by a large number of websites, including Square, Discourse, Groupon, Linked In, Live Nation, Twitch, and Chipotle.

The catch() method is used to handle rejected promises.

Syntax:

catch(onRejected, String label)

Parameters: It takes two parameters.

  • Onrejected: This is a callback back function that is executed when the promise is rejected.
  • String label: This is used to label the promise, this is basically an optional parameter.

Return Value:  It returns a new promise.

Steps to Install and Run Ember.js:

Step 1: To run the following examples you will need to have an ember project with you. To create one, you will need to install ember-cli first. Write the below code in the terminal:

npm install -g ember-cli

Step 2: Now you can create the project by typing in the following piece of code:

ember new <project-name> --lang en

Step 3: To start the server, type:

ember serve

Step 4: After the above query is executed successfully you can check your progress on

http://localhost:4200/

Example 1: Type the following code to use the catch() method to catch the error generated by the reject() method.

app/controller/app.js

Javascript




const Promise1 = new Promise((resolve, reject) => {
    setTimeout(function () {
        Math.random() == 0.5
            ? resolve('Success!')
            : reject(new Error('Something went wrong'));
    }, 1000);
});
 
Promise1
    .then((result) => {
        console.log(result);
    })
    .catch(() => {
        console.log('Error has Occurred');
    });


app/templates/application.hbs

Javascript




{{page-title "Emberjs"}}
 
<div>
    <h2>
        Welcome to the tutorial
        of Promises in Ember.js
    </h2>
</div>


Output: Visit localhost:4200/ to view the output

 

Example 2: Type the following code to use the catch() method to catch the error generated by the reject() method.

apps/controller/app1.js

Javascript




let promise2 = new Promise((resolve, reject) => {
    console.log('Promise 2');
    setTimeout(() => {
        const a = 5;
        a >= 18 ? resolve('Success!') :
            reject(new Error('something has occurred'));
    }, 2000);
});
 
promise2
    .then((result) => {
        console.log(result);
    })
    .catch(() => {
        console.log('Error has Occurred');
    });


app/templates/application.hbs

Javascript




{{page-title "Emberjs"}}
 
<div>
    <h2>Welcome to the tutorial of Promises in Ember.js </h2>
</div>


Output: Visit localhost:4200/ to view the output

 

Reference: https://api.emberjs.com/ember/3.18/classes/Promise/methods/catch?anchor=catch



Last Updated : 09 Feb, 2023
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