Embeer.js MutableArray includes()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。

includes() 方法用于检查给定对象是否存在于数组中。

用法:

includes(obj,startAt)

参数：

obj:要寻找的对象。
startAt:可选的搜索起始索引。

返回：如果数组包含对象，则为 true，否则为 false。

第 1 步：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

步骤 2：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 list

应用程序/路线/list.js


import Route from '@ember/routing/route'; 
  
export default class ListRoute extends Route { 
    list = ['a', 'a', 'v', 'c', 'c', 'a', 'd',  
        'q', 'b', 'z', 'a']; 
    item; 
    idx; 
    model() { 
        return this.list; 
    } 
    setupController(controller, model) { 
        super.setupController(controller, model); 
        controller.set('list', this.list); 
        controller.set('item', this.item); 
        controller.set('idx', this.idx); 
    } 
}

应用程序/控制器/list.js


import Ember from 'ember'; 
import { clear, insertAt, indexOf, lastIndexOf, includes }  
    from '@ember/array'; 
  
export default Ember.Controller.extend({ 
    actions: { 
        insertItem(item, idx) { 
            this.list.insertAt(idx, item); 
        }, 
        getLastIndex(item) { 
            let res = this.list.lastIndexOf(item); 
            alert(res); 
        }, 
        getFirstIndex(item) { 
            let res = this.list.indexOf(item); 
            alert(res); 
        }, 
        clearList() { 
            this.list.clear(); 
        }, 
        contains(item) { 
            let res = this.list.includes(item); 
            alert(`The list ${res ? '' : 'does not'} 
            contains ${item}`); 
        }, 
    }, 
});

应用程序/模板/list.hbs


{{page-title "List"}} 
<h3>Here is a list of Items: </h3> 
<ul> 
    {{#each @model as |i|}} 
        <li>{{i}}</li> 
      {{/each}} 
</ul> 
<br /><br /> 
<div> 
    <label>Enter Item: </label> 
      {{input value=this.item}} 
</div> 
<div> 
    <label>Enter Index: </label> 
      {{input value=this.idx}} 
</div> 
<div> 
    <input
        type="button"
        id="insert-item"
        value="Insert Item"
        {{action "insertItem" this.item this.idx}} 
      /> 
</div> 
<br /><br /> 
<div> 
    <label>Enter Item: </label> 
      {{input value=this.item}} 
</div> 
<div> 
    <input
        type="button"
        id="first-index-item"
        value="Get First Index"
        {{action "getFirstIndex" this.item}} 
      /> 
</div> 
<div> 
    <input
        type="button"
        id="last-index-item"
        value="Get Last Index"
        {{action "getLastIndex" this.item}} 
      /> 
</div> 
<div> 
    <input
        type="button"
        id="contains-item"
        value="Contains?"
        {{action "contains" this.item}} 
      /> 
</div> 
<br /><br /> 
<input type="button" id="clear-items" value="Clear" 
    {{action "clearList"}} /> 
{{outlet}}

输出：访问 localhost:4200/list 查看输出

示例 2：键入以下代码以生成本示例的路由：

ember generate route party

应用程序/路线/party.js


import Route from '@ember/routing/route'; 
  
export default class PartyRoute extends Route { 
    partyItems = [ 
        'Digital Camera', 
        'Jugs, cups & straws', 
        'Cold Drink', 
        'Balloons', 
        'Scissors', 
        'Wine', 
        'Cold Drink', 
        'Table Confetti', 
        'Party Hats', 
        'Wine', 
        'Napkins', 
        'Party Plates', 
        'Speakers', 
        'Wine', 
        'Music System', 
        'Cold Drink', 
        'Cups', 
    ]; 
    item; 
    idx; 
    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); 
    } 
}

应用程序/控制器/party.js


import Ember from 'ember'; 
import { insertAt, indexOf, lastIndexOf, includes } 
    from '@ember/array'; 
  
export default Ember.Controller.extend({ 
    actions: { 
        insertItem(item, idx) { 
            this.partyItems.insertAt(idx, item); 
        }, 
        getLastIndex(item) { 
            let res = this.partyItems.lastIndexOf(item); 
            alert(res); 
        }, 
        getFirstIndex(item) { 
            let res = this.partyItems.indexOf(item); 
            alert(res); 
        }, 
        clearpartyItems() { 
            this.partyItems.clear(); 
        }, 
        contains(item) { 
            let res = this.partyItems.includes(item); 
            alert(`The partyItems ${res ? '' : 'does not'} 
            contains ${item}`); 
        }, 
    }, 
});

应用程序/模板/party.hbs


{{page-title "Party"}} 
<h3>Here is a list of items: </h3> 
<ul> 
    {{#each @model as |party|}} 
        <li>{{party}}</li> 
      {{/each}} 
</ul> 
<br /><br /> 
<div> 
    <label>Enter Item: </label> 
      {{input value=this.item}} 
</div> 
<div> 
    <label>Enter Index: </label> 
      {{input value=this.idx}} 
</div> 
<div> 
    <input
        type="button"
        id="insert-item"
        value="Insert Item"
        {{action "insertItem" this.item this.idx}} 
      /> 
</div> 
<br /><br /> 
<div> 
    <label>Enter Item: </label> 
      {{input value=this.item}} 
</div> 
<div> 
    <input
        type="button"
        id="first-index-item"
        value="Get First Index"
        {{action "getFirstIndex" this.item}} 
      /> 
</div> 
<div> 
    <input
          type="button"
        id="last-index-item"
        value="Get Last Index"
        {{action "getLastIndex" this.item}} 
      /> 
</div> 
<div> 
    <input
        type="button"
        id="contains-item"
        value="Contains?"
        {{action "contains" this.item}} 
      /> 
</div> 
<br /><br /> 
{{outlet}}

输出：访问 localhost:4200/party 查看输出

参考： https://api.emberjs.com/ember/4.4/classes/MutableArray/methods

相关用法

注：本文由纯净天空筛选整理自aayushmohansinha大神的英文原创作品 Ember.js MutableArray includes() Method。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。