Ember.js Ember.NativeArray lastIndexOf() 方法

Ember.js 是一个开源的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是最常用的前端应用框架之一。它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等。

lastIndexOf() 方法用于在数组中查找传递对象的最后一个出现的索引。

语法：

lastIndexOf( object, startAt );

参数：

object: 我们想要查找的对象。
startAt: 从哪个索引开始查找。

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。

步骤1： 要运行以下示例，您需要拥有一个ember项目。为此，您首先需要安装ember-cli。在终端中写入以下代码：

npm install ember-cli

步骤2： 现在，您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 StudentsRoute extends Route { 
    partyItems = [ 
        'Digital Camera', 
        'Jugs, cups & straws', 
        'Balloons', 
        'Cups', 
        'Scissors', 
        'Cold Drink', 
        'Table Confetti', 
        'Party Hats', 
        'Wine', 
        'Napkins', 
        'Scissors', 
        'Party Plates', 
        'Speakers', 
        'Music System', 
        'Cold Drink', 
        'Cups', 
        'Wine', 
    ]; 
    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); 
    } 
}

app/controllers/lastIndexOf1.js

import Ember from "ember"; 
  
export default Ember.Controller.extend({ 
    actions: { 
        last_index(data) { 
            let ans = this.partyItems.lastIndexOf(data); 
            alert(`Last Index of item is  ${ans}`);         },         check_items(data) {             let temp = this.partyItems.includes(data)             alert(temp ? "Item is present in list" :                  "Item is not Present in list")         },         find_index(data) {             let temp = this.partyItems.indexOf(data);             alert(`Index of$ {data} is ${temp}`) 
        }, 
  
    }, 
});

app/templates/lastIndexOf1.hbs

{{page-title "lastIndexOf"}} 
<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="Check Item"
      {{action "check_items" this.temp}} 
/> 
<br /><br /> 
<div> 
    <label>Enter Item: </label> 
      {{input value=this.temp1}} 
</div> 
<input 
    type="button"
      id="find-Index"
      value="Find Index Of Item"
      {{action "find_index" this.temp1}} 
/> 
<br /><br /> 
<div> 
    <label>Enter Item: </label> 
      {{input value=this.temp2}} 
</div> 
<input 
    type="button"
      id="find-last"
      value="Find last Index"
      {{action "last_index" this.temp2}} 
/> 
{{outlet}}

输出： 访问localhost:4200/lastIndexOf1来查看输出。

Ember.js Ember.NativeArray lastIndexOf() 方法

范例2： 输入以下代码以生成此范例的路由：

ember generate route lastIndexOf2

app/routes/lastIndexOf2.js

import Route from '@ember/routing/route'; 
  
export default class PartyRoute extends Route { 
    partyItems = [ 
        'Oxygen', 
        'The Thing', 
        'Source Code', 
        'Infine', 
        'Ad Astra', 
        'Tenet', 
        'SpiderHead', 
        'The Thing', 
        'A Quiet Place', 
        'The Invisible Man', 
        'Looper', 
        'Infine', 
        '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); 
    } 
}

app/controllers/lastIndexOf2.js

import Ember from 'ember'; 
import { } from '@ember/array'; 
  
export default Ember.Controller.extend({ 
    actions: { 
        check_index(item) { 
            let temp = this.partyItems.indexOf(item); 
            alert(`Index of Movie is  ${temp}`);         },         check_movie(item) {             let temp = this.partyItems.includes(item);             alert(temp ? 'Movie is present in watch list' :                  'Movie is not Present in watch list');         },         check_last(item) {             let temp = this.partyItems.lastIndexOf(item);             alert(`Last Index of Movie is$ {temp}`); 
        }, 
    }, 
});

app/templates/lastIndexOf2.hbs

{{page-title "lastIndexOf"}} 
<h3>Here is a list of items: </h3> 
<ul> 
    {{#each @model as |party|}} 
        <li>{{party}}</li> 
    {{/each}} 
</ul> 
<br /><br /> 
<div> 
    <label>Enter Movie: </label> 
    {{input value=this.temp}} 
</div> 
<input 
    type="button"
    id="find-Index"
    value="Find Movie Index"
    {{action "check_index" this.temp}} 
/> 
<br /><br /> 
<div> 
    <label>Enter Movie: </label> 
    {{input value=this.temp1}} 
</div> 
<input 
    type="button"
    id="check-movie"
    value="Check Movie"
    {{action "check_movie" this.temp1}} 
/> 
<br /><br /> 
<div> 
    <label>Enter Item: </label> 
    {{input value=this.temp2}} 
</div> 
<input 
    type="button"
    id="check-last"
    value="Check Last Index of Movie"
    {{action "check_last" this.temp2}} 
/> 
{{outlet}}

输出: 访问 localhost:4200/lastIndexOf2 查看输出结果

Ember.js Ember.NativeArray lastIndexOf() 方法