Ember.js EmberArray map() 方法

Ember.js 是一个开源JavaScript框架，用于开发基于模型-视图-控制器（MVC）架构的大型客户端Web应用程序。 Ember.js是最广泛使用的前端应用框架之一。它旨在加快开发速度并提高生产力。目前，许多网站都使用它，包括Square、Discourse、Groupon、Linked In、Live Nation、Twitch和Chipotle。

map() 方法用于将枚举中的所有项目映射到另一个值。

语法:

map( callback, target );

参数：

callback： 它是在每个项目上执行的回调函数。
target： 它是回调函数将执行的目标项目。

返回值： 映射后的数组。

安装和运行Ember.js的步骤：

要运行下面的示例，您需要先拥有一个Ember项目。要创建一个项目，您需要首先安装ember-cli。在终端中输入以下代码：

npm install ember-cli

现在你可以通过键入以下代码来创建项目：

ember new <project-name> --lang en

要启动服务器，请键入：

ember serve

示例1

输入以下代码来生成此示例的路由：

ember generate route map1

app/routes/map1.js

import Route from '@ember/routing/route'; 
  
export default class WebsitesRoute 
    extends Route { 
    food = [ 
        { 
            food: 'apple', 
            quant: 1.5, 
            Bucket: 1, 
        }, 
        { 
            food: 'Potato', 
            quant: 3, 
            Bucket: 2, 
        }, 
        { 
            food: 'Banana', 
            quant: 2, 
            Bucket: 1, 
        }, 
        { 
            food: 'grapes', 
            quant: 3, 
            Bucket: 2, 
        }, 
        { 
            food: 'Orange', 
            quant: 2, 
            Bucket: 1, 
        }, 
        { 
            food: 'Pine-apple', 
            quant: 1, 
            Bucket: 2, 
        }, 
        { 
            food: 'bean', 
            quant: 3, 
            Bucket: 2, 
        }, 
    ]; 
    temp; 
    model() { 
        return this.food; 
    } 
    setupController(controller, model) { 
        super.setupController(controller, model); 
        controller.set('food', this.food); 
        controller.set('temp', this.temp); 
        controller.set('temp2', this.temp2); 
    } 
}

app/controllers/map1.js

import Ember from 'ember'; 
import { map } from '@ember/array'; 
  
export default Ember.Controller.extend({ 
    actions: { 
        increase_quant(data) { 
            this.food.map((item) => 
                Ember.set(item, 'quant', 
                    (item.quant) + +data)); 
  
        }, 
        shift_bucket() { 
            this.food.map((item) => 
                Ember.set(item, 'Bucket',  
                 item.Bucket == 1 
                    ? 2 : 1)); 
  
        }, 
    }, 
});

app/templates/map1.hbs

{{page-title "invoke"}} 
  
<h2>List of Item with Quantity </h2> 
  
<table> 
    <tr> 
        <th>Name</th> 
        <th>Quantity</th> 
        <th>Bucket</th> 
    </tr> 
    {{#each @model as |Eatable|}} 
        <tr> 
            <td>{{Eatable.food}}</td> 
            <td>{{Eatable.quant}}</td> 
            <td>{{Eatable.Bucket}}</td> 
  
        </tr> 
    {{/each}} 
</table> 
<br /> 
  
<div> 
    <label>Enter quantity: </label> 
    {{input value=this.qut}} 
</div> 
<input 
    type="button"
    id="greet"
    value="Increase_quant"
    {{action "increase_quant" this.qut}} 
/> 
  
<br /><br /> 
<input 
    type="button"
    id="greet"
    value="Shift Bucket"
    {{action "shift_bucket"}} 
/> 
{{outlet}}

输出： 访问 localhost：4200/map1 查看输出

Ember.js EmberArray map() 方法

示例2

输入以下代码以生成此示例的路由：

ember generate route mapBy2

app/routes/map2.js

import Route from '@ember/routing/route'; 
  
export default class StudentsRoute extends Route { 
    students = [ 
        { 
            name: 'Aakash', 
            gender: 'M', 
            class: 10, 
            grade: 'A', 
        }, 
        { 
            name: 'Soniya', 
            gender: 'F', 
            class: 8, 
            grade: 'C', 
        }, 
        { 
            name: 'Sita', 
            gender: 'F', 
            class: 10, 
            grade: 'A', 
        }, 
        { 
            name: 'Ram', 
            gender: 'M', 
            class: 10, 
            grade: 'A', 
        }, 
        { 
            name: 'Esnoor', 
            gender: 'M', 
            class: 9, 
            grade: 'C', 
        }, 
        { 
            name: 'Isha', 
            gender: 'F', 
            class: 19, 
            grade: 'B', 
        }, 
        { 
            name: 'Doman', 
            gender: 'M', 
            class: 12, 
            grade: 'B', 
        }, 
        { 
            name: 'Lolu', 
            gender: 'M', 
            class: 10, 
            grade: 'A', 
        }, 
        { 
            name: 'Lucky', 
            gender: 'M', 
            class: 11, 
            grade: 'F', 
        }, 
        { 
            name: 'Neha', 
            gender: 'F', 
            class: 10, 
            grade: 'B', 
        }, 
        { 
            name: 'Balit', 
            gender: 'M', 
            class: 12, 
            grade: 'F', 
        }, 
        { 
            name: 'Hillier Buchanan', 
            gender: 'M', 
            class: 12, 
            grade: 'A', 
        }, 
        { 
            name: 'Aman', 
            gender: 'M', 
            class: 11, 
            grade: 'B', 
        }, 
        { 
            name: 'Anuj', 
            gender: 'M', 
            class: 12, 
            grade: 'F', 
        }, 
        { 
            name: 'Satyam', 
            gender: 'M', 
            class: 12, 
            grade: 'F', 
        }, 
        { 
            name: 'Aayush', 
            gender: 'M', 
            class: 12, 
            grade: 'C', 
        }, 
    ]; 
    temp2; 
    model() { 
        return this.students; 
    } 
    setupController(controller, model) { 
        super.setupController(controller, model); 
        controller.set('students', this.students); 
        controller.set('temp2', this.temp2); 
    } 
}

app/controllers/map2.js

import Ember from "ember"; 
import { filter } from "@ember/array"; 
  
export default Ember.Controller.extend({ 
    actions: { 
        allPass() { 
            let ans = ''; 
            let temp = this.students.map((item) => 
                item.grade == 'F' ? ans += item.name 
                    + '\n' : ''); 
            alert(ans); 
        }, 
        allFemale() { 
            let ans = ''; 
            let temp = this.students.map((item) 
                => item.gender == 'F' ? 
                    ans += item.name + '\n' : ''); 
            alert(ans); 
        }, 
        allClass(data) { 
            let ans = ''; 
            let temp = this.students.filter((item) => 
                item.class == JSON.parse(data) ? 
                    ans += item.name + '\n' : ''); 
            alert(ans); 
        }, 
    } 
});

app/templates/map2.hbs

{{page-title "Students"}} 
<h3>List of Students: </h3> 
<br /><br /> 
<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 /> 
<input 
    type="button"
    id="all-pass"
    value="Failed Student"
    {{action "allPass"}} 
/> 
<br /><br /> 
<input 
    type="button"
    id="all-female"
    value="All are Female"
    {{action "allFemale"}} 
/> 
<br /><br /> 
<div> 
    <label>Enter Class: </label> 
    {{input value=this.temp2}} 
</div> 
<br /> 
<input 
    type="button"
    id="all-class"
    value="All are in Same class"
    {{action "allClass" this.temp2}} 
/> 
{{outlet}}