Embeer.js ArrayProxy length用法及代码示例

Ember.js 是一个开源 JavaScript 框架，用于开发基于 Model-View-Controller (MVC) 架构的大型客户端 Web 应用程序。 Ember.js是使用最广泛的前端应用框架之一。它的目的是加速开发并提高生产力。目前，它被大量网站使用，包括 Square、Discourse、Groupon、Linked In、Live Nation、Twitch 和 Chipotle。

length 属性是显示数组中元素总数的属性。

用法:

Array.length;

参数：

Array: 这是我们想要长度的数组。

安装和运行 Ember.js 的步骤：

要运行以下示例，您需要有一个 ember 项目。要创建一个，您需要先安装ember-cli。在终端中写入以下代码：

npm install ember-cli

现在您可以通过输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：键入以下代码以生成本示例的路由：

ember generate route len1

应用程序/路线/len1.js


import Route from "@ember/routing/route"; 
  
export default class StudentsRoute extends Route { 
    partyItems = [ 
        'Digital Camera', 
        'Jugs, cups & straws', 
        'Balloons', 
        'Scissors', 
        'Cold Drink', 
        'Table Confetti', 
        'Party Hats', 
        'Wine', 
        'Napkins', 
        'Party Plates', 
        'Speakers', 
        'Music System', 
        'Cups', 
    ]; 
    len; 
    model() { 
        return this.partyItems; 
    } 
    setupController(controller, model) { 
        super.setupController(controller, model); 
        controller.set("partyItems", this.partyItems); 
        controller.set("len", this.len); 
        controller.set("item", this.item); 
    } 
}

应用程序/控制器/len1.js


import Ember from "ember"; 
  
export default Ember.Controller.extend({ 
    actions: { 
        show_first(){ 
            let ans = this.partyItems.get('firstObject') ; 
            alert(ans) 
        }, 
        show_last() { 
            let ans = this.partyItems.get('lastObject'); 
            alert(ans) 
              }, 
        show_len() { 
            let S_len = this.partyItems.length; 
            this.set('len',S_len) 
            alert('Length of List is '+this.len); 
        }, 
        check_items(data ){ 
            let temp = this.partyItems.without(data) 
            alert(temp.join('\n')) 
        }, 
    show() { 
      let temp = this.partyItems.get('[]'); 
      alert(temp.join('\n')) 
        }, 
    }, 
});

应用程序/模板/len1.hbs


{{page-title "length"}} 
<h3>List of Items: </h3> 
  
<table> 
<ul>     
    {{#each @model as |student|}} 
      
        <li>{{student}}</li> 
      
    {{/each}} 
    </ul> 
</table> 
<br /><br /> 
<div> 
    <label>Enter Item: </label> 
    {{input value=this.temp}} 
</div> 
<input 
    type="button"
    id="check-atIndex"
    value="Print Except this Item"
    {{action "check_items" this.temp}} 
/> 
<br /><br /> 
<input 
    type="button"
    id="show-item"
    value="Pop up All Items"
    {{action "show"}} 
/> 
<br /><br /> 
<input 
    type="button"
    id="first-item"
    value="Show First Item"
    {{action "show_first"}} 
/> 
<br /><br /> 
<input 
    type="button"
    id="show-item2"
    value="Show Last Item"
    {{action "show_last"}} 
/> 
  
<br /><br /> 
<input 
    type="button"
    id="print-list"
    value="Print length of List"
    {{action "show_len"}} 
/> 
{{outlet}}

输出：访问 localhost:4200/len1 查看输出

Ember.js ArrayProxy 长度属性

示例 2：键入以下代码以生成本示例的路由：

ember generate route len2

应用程序/路线/len2.js


import Route from '@ember/routing/route'; 
  
export default class PartyRoute extends Route { 
    partyItems = [ 
        'Oxygen', 
        'Source Code', 
        'Infine', 
        'Tenet', 
        'SpiderHead', 
        'The Thing', 
        'A Quiet Place', 
        'The Invisible Man', 
        'Looper', 
        'Ad Astra'
    ]; 
    item; 
    idx; 
    len; 
    model() { 
        return this.partyItems; 
    } 
    setupController(controller, model) { 
        super.setupController(controller, model); 
        controller.set('partyItems', this.partyItems); 
        controller.set('item', this.item); 
        controller.set('idx', this.idx); 
        controller.set('len', this.len); 
    } 
}

应用程序/控制器/len2.js


import Ember from 'ember'; 
import { } from '@ember/array'; 
  
export default Ember.Controller.extend({ 
    actions: { 
        remove_Item(item) { 
            this.partyItems.set('[]', 
            this.partyItems.without(item)); 
        }, 
        print_len() { 
            alert( this.partyItems.length) 
              
        }, 
        print_first() { 
            let ans = this.partyItems.get('firstObject'); 
            alert(ans) 
        }, 
        print_last() { 
            let ans = this.partyItems.get('lastObject'); 
            alert(ans) 
        }, 
    }, 
});

应用程序/模板/len2.hbs


{{page-title "length"}} 
<h3>Here is a list of items: </h3> 
<ul> 
    {{#each @model as |party|}} 
        <li>{{party}}</li> 
    {{/each}} 
</ul> 
<br /> 
<div> 
    <label>Enter value: </label> 
    {{input value=this.item}} 
</div> 
<div> 
    <input 
        type="button"
        id="search-item"
        value="Remove this item"
        {{action "remove_Item" this.item}} 
    /> 
</div> 
<br/> 
<div> 
    <input 
        type="button"
        id="len-list"
        value="Print Total length of list"
        {{action "print_len"}} 
    /> 
</div> 
<br/> 
<div> 
    <input 
        type="button"
        id="list-first"
        value="Print first element of list"
        {{action "print_first"}} 
    /> 
</div> 
<br/> 
<div> 
    <input 
        type="button"
        id="list-last"
        value="Print last element of list"
        {{action "print_last"}} 
    /> 
</div> 
{{outlet}}

输出：访问 localhost:4200/len2 查看输出

Ember.js ArrayProxy 长度属性

参考：https://api.emberjs.com/ember/4.6/classes/ArrayProxy/properties?anchor=length

相关用法

注：本文由纯净天空筛选整理自satyam00so大神的英文原创作品 Ember.js ArrayProxy length Property。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。