Ember.js Ember.Templates.helpers fn() Method

Ember.js is an open-source JavaScript framework used for developing large client-side web applications which is 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 fn() method is used to ensure a function that you are passing off to another component or helper has access to the arguments that are available in the templates.

Syntax:

<SomeComponent @args={{fn this.function args }} />

Parameters: 

• this.function: It is the function to which we are ensuring the argument. 
• args: It is an argument that is passing to function.

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 ember-cli

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

ember new <project-name> --lang en

To start the server, type:

ember server

Example 1: Type the following code to generate the route for this example:

ember generate route fn1

app/components/compact.js

Javascript

import Component from '@glimmer/component';
import { tracked } from '@glimmer/tracking';
import { action } from '@ember/object';

export default class extends Component {
    student = [{
        "name": "Sam Snehil",
        "age": 21
    },
    {
        "name": "Satyam Sahu",
        "age": 23
    },
    {
        "name": "Sohan Argrwal",
        "age": 25
    },
    {
        "name": "Sreya Sarma",
        "age": 19
    }];


    print(item) {

        let ans = ''
        item.map((student) => ans += student.name + ` is `
            + student.age + ' year old ' + '\n')
        alert(ans);
    }
}

app/components/compact.hbs

HTML

{{yield}}
<table>
        <tr>
        <th>Name</th>
        <th>Class</th>
    </tr>
      {{#each this.student as |detail|}}
    <tr>
        <td>{{detail.name}}</td>
        <td>{{detail.age}}</td>
    </tr>
    {{/each}}
    </table>
<br/>
<input type="button"
        id="set-code"
        value="Introduction of Each Student"
{{on 'click' (fn this.print this.student)}}/>

app/templates/fn1.hbs

HTML

<Compact>
    <h1>
    List of Student :
    </h1>
</Compact>
{{outlet}}

Output:

Ember.js Ember.Templates.helpers fn() Method

Example 2: Type the following code to generate the route for this example:

ember generate route fn2

app/components/compact2.js

Javascript

import Component from '@glimmer/component';
import { tracked } from '@glimmer/tracking';
import { action } from '@ember/object';

export default class extends Component {
    food = [{
        "food": "Banana",
        "Quant": 5
    },
    {
        "food": "Pine-apple",
        "Quant": 2
    },
    {
        "food": "Apple",
        "Quant": 7
    },
    {
        "food": "Mango",
        "Quant": 4
    }];

    list(temp) {
        let ans = temp.mapBy('food');
        alert(ans.join('\n'))
    }
}

app/components/compact2.hbs

HTML

{{yield}}
<table>
    <tr>
          <th>Food</th>
        <th>Quantity</th>
      </tr>
      {{#each this.food as |detail|}}
    <tr>
        <td>{{detail.food}}</td>
          <td>{{detail.Quant}}</td>
    </tr>
      {{/each}}
</table>
<br />
<input
    type="button"
      id="set-code"
      value="List all Fruits"
      {{on "click" (fn this.list this.food)}}
/>

app/templates/fn2.hbs

Javascript

<Compact2 >
    <h1>
        List of Foods:
    </h1>
</Compact2>
{{outlet}}

Output:

Ember.js Ember.Templates.helpers fn() Method

Reference: https://api.emberjs.com/ember/4.4/classes/Ember.Templates.helpers/methods/fn?anchor=fn