Ember.js ArrayProxy lastIndexOf() 方法

Ember.js 是一种基于模型-视图-控制器（MVC）架构的开源JavaScript框架，用于开发大型客户端Web应用程序。Ember.js 是最常用的前端应用程序框架之一，旨在加快开发速度和提高生产力。目前，它被许多网站使用，包括Square，Discourse，Groupon，Linked In，Live Nation，Twitch和Chipotle。

lastIndexOf() 方法用于获取给定对象的最后一次出现的索引。

语法：

lastIndexOf( object, startAt );

参数:

object: 它是我们想要索引的对象。
startAt: 它是要搜索的起始位置。

返回值: 对象在数组中的最后一个索引，如果未找到则返回-1。

要运行以下示例，您需要一个ember项目。要创建一个，您首先需要安装ember-cli。在终端中写下面的代码:

npm install ember-cli

现在你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，请输入：

ember serve

示例1

输入以下代码以生成此示例的路由：

ember generate route lastIndexOf1

app/routes/lastIndexOf1.js

import Route from '@ember/routing/route'; 
  
export default class ListRoute extends Route { 
    list = [1, 2, 3, 5, 6, 2, 1, 7, 8, 9, 8]; 
    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); 
    } 
}

app/controllers/lastIndexOf1.js

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

app/templates/lastIndexOf1.hbs

{{page-title "LastIndexOf"}} 
<h3>Here is a list of Items: </h3> 
<ul> 
    {{#each @model as |i|}} 
        <li>{{i}}</li> 
    {{/each}} 
</ul> 
<br/> 
<div> 
    <label>Enter Item: </label> 
    {{input value=this.item2}} 
</div> 
<div> 
    <input 
        type="button"
        id="contains-item"
        value="Contains?"
        {{action "contains" this.item2}} 
    /> 
</div> 
<br/> 
<div> 
    <input 
        type="button"
        id="check-item"
        value="Check Last Index"
        {{action "checkLastIndex" this.item2}} 
    /> 
</div> 
<br /> 
<div> 
    <label>Enter Item: </label> 
    {{input value=this.item}} 
</div> 
<div> 
    <input 
        type="button"
        id="insert-item"
        value="Insert Item"
        {{action "insertItem" this.item }} 
    /> 
</div> 
<br /> 
<input type="button" id="clear-items" 
    value="Clear"
    {{action "clearList"}} /> 
{{outlet}}

输出： 访问 localhost:4200/lastIndexOf1 查看输出结果

Ember.js ArrayProxy lastIndexOf() 方法

示例2

键入以下代码以生成此示例的路由：

ember generate route lastIndexOf2

app/routes/lastIndexOf2.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'
    ]; 
  temp = [ 
        'Shutter Island', 
        'Matrix', 
        'Avatar', 
        'Fantastic Beast', 
        'Avengers', 
        'Fantastic four', 
        'HulK', 
        'Superman', 
        'Spiderman', 
        'The Batman'
    ]; 
    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); 
    controller.set('temp', this.temp); 
    } 
}

app/controllers/lastIndexOf2.js

import Ember from 'ember'; 
import { pushObject, pushObjects, lastIndexOf, includes } 
    from '@ember/array'; 
  
export default Ember.Controller.extend({ 
    actions: { 
        insertItem(item) { 
            this.partyItems.pushObject(item); 
        }, 
        push_item(data) { 
            this.partyItems.pushObjects(data); 
        }, 
        contains(item) { 
            let res = this.partyItems.includes(item); 
            alert(`The List  ${res ? '' : 'does not'} contains$ {item}`); 
        }, 
        checkLastindex(item) { 
            let res = this.partyItems.lastIndexOf(item); 
            alert(res); 
        }, 
    }, 
});

app/templates/lastIndexOf2.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> 
    <input 
        type="button"
        id="insert-item"
        value="Insert Item"
        {{action "insertItem" this.item}} 
    /> 
</div> 
<br /> 
<div> 
    <label>Enter Item: </label> 
    {{input value=this.item2}} 
</div> 
<div> 
    <input 
        type="button"
        id="contains-item"
        value="Contains?"
        {{action "contains" this.item2}} 
    /> 
</div> 
<br/> 
<div> 
    <input 
        type="button"
        id="get-item"
        value="Get Last Index"
        {{action "checkLastindex" this.item2}} 
    /> 
</div> 
<br /> 
<input 
        type="button"
        id="contains-item"
        value="Add Movies"
        {{action "push_item" this.temp}} 
    /> 
{{outlet}}

输出： 访问localhost:4200/lastIndexOf2来查看输出

Ember.js ArrayProxy lastIndexOf() 方法