Ember.js ArrayProxy mapBy() 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 mapBy() method is used to get the all values of named properties in the enumeration.
Syntax:
mapBy( key );
Parameters:
- key: It is the name of the property whose value we want.
Return Value: Return mapped array.
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 serve
Example 1: Type the following code to generate the route for this example:
ember generate route mapBy1
app/routes/mapBy1.js
import Route from "@ember/routing/route" ; export default class StudentsRoute extends Route { students = [ { name: "Aaush Somankar" , gender: "M" , class: 12, grade: "A" , }, { name: "Aman Prakash" , gender: "M" , class: 10, grade: "A" , }, { name: "Siya guru" , gender: "F" , class: 11, grade: "B" , }, { name: "Ramesh verma" , gender: "M" , class: 10, grade: "A" , }, { name: "Esnoor" , gender: "M" , class: 9, grade: "F" , }, { name: "Balit" , gender: "M" , class: 10, grade: "A" , }, { name: "Dora" , gender: "F" , class: 12, grade: "F" , }, { name: "Lalu" , gender: "F" , class: 8, grade: "A" , }, { name: "Pokhraj" , gender: "M" , class: 11, grade: "F" , }, { name: "Citu" , gender: "M" , class: 8, grade: "C" , }, { name: "Rahul" , gender: "M" , class: 9, grade: "A" , }, { name: "Ram" , gender: "M" , class: 12, grade: "A" , }, { name: "Priti" , gender: "F" , class: 9, grade: "F" , }, { name: "Flip" , gender: "M" , class: 9, grade: "B" , }, { name: "Sita" , gender: "F" , class: 8, grade: "A" , }, { name: "Aashray" , gender: "M" , class: 12, grade: "C" , }, { name: "Suneel" , gender: "M" , class: 8, grade: "C" , }, ]; convert(string) { this .item = string.split( "," ).map((item) => item.trim()); return this .item; } model() { return this .students; } setupController(controller, model) { super .setupController(controller, model); controller.set( "students" , this .students); controller.set( "convert" , this .convert); controller.set( "item" , this .item); } } |
app/controllers/mapBy1.js
import Ember from "ember" ; export default Ember.Controller.extend({ actions: { getAllNames() { let res = this .students.mapBy( 'name' ); alert(res.join( '\n' )); }, allPass() { let temp = '' ; let tempItems = this .students.map((item) => item.grade == 'F' ? temp += item.name + '\n' : temp); alert(temp); }, remove() { this .students.popObject(); }, check_item(idx) { let temp = this .students.objectAt(JSON.parse(idx)); alert(temp.name) }, check_items(idx) { idx = this .convert(idx); let temp = this .students.objectsAt(idx); let ans = temp.mapBy( 'name' ) alert(ans.join( '\n' )) }, }, }); |
app/templates/mapBy1.hbs
{{page-title "mapBy" }} <h3>List of Students: </h3> <table> <tr> <th>Name</th> <th>Class</th> <th>Gender</th> <th>Grade</th> </tr> {{ #each @model as |student|}} <tr> <td>{{student.name}}</td> <td>{{student.class}}</td> <td>{{student.gender}}</td> <td>{{student.grade}}</td> </tr> {{/each}} </table> <br /><br /> <input type= "button" id= "get-all" value= "Get All Names" {{action "getAllNames" }} /> <br /><br /> <input type= "button" id= "all-pass" value= "Did Everyone Pass?" {{action "allPass" }} /> <br /><br /> <div> <label>Enter index: </label> {{input value= this .temp}} </div> <input type= "button" id= "increase-pocket-money" value= "Get Person at Index" {{action "check_item" this .temp}} /> <br /><br /> <div> <label>Enter indexs: </label> {{input value= this .temp2}} </div> <input type= "button" id= "check-atIndex" value= "Check at indexes" {{action "check_items" this .temp2}} /> <br /><br /> <input type= "button" id= "remove-last" value= "Remove Last Student" {{action "remove" }} /> {{outlet}} |
Output: Visit localhost:4200/mapBy1 to view the output
Example 2: Type the following code to generate the route for this example:
ember generate route mapBy2
app/routes/mapBy2.js
import Route from '@ember/routing/route' ; import { classify, w } from '@ember/string' ; import { mapBy } from '@ember/array' ; export default class LanguagesRoute extends Route { name = `Hindi Korean Marathi Telugu Portuguese Turkish Bengali Spanish`; num = `343.9 81.7 83.1 82.0 232.4 82.3 233.7 474`; languages = []; initLanguages() { this .languages = []; this .name = w( this .name); this .num = w( this .num); for (let i = 0; i < this .name.length; i++) { let obj = new Object(); obj[ 'name' ] = classify( this .name[i]); obj[ 'num' ] = this .num[i]; this .languages.pushObject(obj); } } temp1; convert(string) { this .item = string.split( "," ).map((item) => item.trim()); return this .item; } model() { this .initLanguages(); return this .languages; } setupController(controller, model) { super .setupController(controller, model); controller.set( 'languages' , this .languages); controller.set( 'temp1' , this .temp1); controller.set( 'convert' , this .convert) } } |
app/controllers/mapBy2.js
import Ember from 'ember' ; import { mapBy } from '@ember/array' ; export default Ember.Controller.extend({ actions: { get_Name() { let ans = this .languages.mapBy( 'name' ); alert(ans.join( '\n' )); }, get_most() { let temp = 0; let tempItems = this .languages.map((item) => temp < JSON.parse(item.num) ? temp = item.name : temp); alert(temp); }, remove() { this .languages.popObject(); }, check_item(idx) { let temp = this .languages.objectAt(JSON.parse(idx)); alert(temp.name) }, check_items(idx) { idx = this .convert(idx); let temp = this .languages.objectsAt(idx); let ans = temp.mapBy( 'name' ) alert(ans.join( '\n' )) }, }, }); |
app/templates/mapBy2.hbs
{{page-title "mapBy" }} <h2>Spoken Languages in the World</h2> <table style= "border: 2px solid black;padding: 30px;" > <tr> <th>Language</th> <th>Native Speakers ( in Millions)</th> </tr> {{ #each @model as |language|}} <tr> <td>{{language.name}}</td> <td>{{language.num}}</td> </tr> {{/each}} </table> <br /><br /> <div> <label>Enter index: </label> {{input value= this .temp}} </div> <input type= "button" id= "increase-pocket-money" value= "Get Language at Index" {{action "check_item" this .temp}} /> <br /><br /> <div> <label>Enter indexs: </label> {{input value= this .temp2}} </div> <input type= "button" id= "check-atIndex" value= "Check at indexes" {{action "check_items" this .temp2}} /> <br /> <br /> <div> <input type= "button" id= "check-fruit" value= "Check Most speaking Language" {{action "get_most" }} /> </div> <br /> <div> <input type= "button" id= "remove-item" value= "Remove Last Element" {{action "remove" }} /> </div> <br /> <div> <input type= "button" id= "show-lang" value= "Show Language" {{action "get_Name" }} /> </div> {{outlet}} |
Output: Visit localhost:4200/mapBy2 to view the output
Reference: https://api.emberjs.com/ember/4.6/classes/ArrayProxy/methods/mapBy?anchor=mapBy