Ember.js MutableArray的insertAt()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是最广泛使用的前端应用程序框架之一。它旨在加快开发速度并提高生产力。目前，它被许多网站使用，包括Square、Discourse、Groupon、LinkedIn、Live Nation、Twitch和Chipotle。

insertAt()方法 用于在数组中的特定位置插入一个对象。

语法：

insertAt(idx,obj)

参数：

idx： 插入操作将发生的索引。
obj： 要插入的对象。

返回值： 接收者。

步骤1： 要运行以下示例，您需要拥有一个 ember 项目。要创建一个项目，您需要先安装 ember-cli。在终端中写入以下代码：

npm install ember-cli

步骤2： 现在你可以通过输入以下代码来创建项目：

ember new <project-name> --lang en

启动服务器，输入以下命令：

ember serve

示例1

输入以下代码以生成此示例的路线：

ember generate route list

app/routes/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); 
    } 
}

app/controllers/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}`); 
        }, 
    }, 
});

app/template/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

Ember.js MutableArray的insertAt()方法

示例2

输入以下代码来生成此示例的路由：

ember generate route party

app/routes/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); 
    } 
}

app/controllers/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}`); 
        }, 
    }, 
});

app/template/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 查看输出结果

Ember.js MutableArray的insertAt()方法