Embeer.js EmberArray objectsAt()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。

objectsAt() 方法用于获取给定索引数组的项目。

用法:

objectsAt(indexes)

参数：

indexes: 需要获取对象的索引。

返回：退回的物品。

安装和运行 Ember.js 的步骤：

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

第 2 步：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 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", 
        "Balloons", 
        "Scissors", 
        "Cold Drink", 
        "Table Confetti", 
        "Party Hats", 
        "Wine", 
        "Napkins", 
        "Party Plates", 
        "Speakers", 
        "Music System", 
        "Cups", 
    ]; 
    itemString; 
    itemList; 
    start; 
    end; 
    helper(itemString) { 
        this.itemList = itemString.split(","); 
        for (let i = 0; i < this.itemList.length; i++) 
            this.itemList[i] = this.itemList[i].trim(); 
        return this.itemList; 
    } 
    model() { 
        return this.partyItems; 
    } 
    setupController(controller, model) { 
        this._super(controller, model); 
        controller.set("helper", this.helper); 
        controller.set("partyItems", this.partyItems); 
        controller.set("itemString", this.itemString); 
        controller.set("itemList", this.itemList); 
        controller.set("start", this.start); 
        controller.set("end", this.end); 
    } 
}

应用程序/控制器/party.js


import Ember from "ember"; 
import { 
    objectsAt, 
    removeObject, 
    removeObjects, 
    slice, 
    reverseObjects, 
    setObjects, 
    reject, 
} from "@ember/array"; 
  
export default Ember.Controller.extend({ 
    actions: { 
        getItems(itemString) { 
            this.itemList = this.helper(itemString); 
            for (let i = 0; i < this.itemList.length; i++) 
                this.itemList[i] = 
                parseInt(this.itemList[i]); 
            let tempItems =  
                this.partyItems.objectsAt(this.itemList); 
            let str = ""; 
            for (let i = 0; i < tempItems.length; i++) 
                str += tempItems[i] + "\n"; 
            alert(str); 
        }, 
        removeItems(itemString) { 
            this.itemList = this.helper(itemString); 
            if (this.itemList.length == 1) 
                this.partyItems.removeObject( 
                    this.itemList[0]); 
            else this.partyItems.removeObjects( 
                this.itemList); 
            this.set("itemString", ""); 
        }, 
        sliceItems(start, end) { 
            let tempItems = this.partyItems.slice(start, end); 
            let str = ""; 
            for (let i = 0; i < tempItems.length; i++) 
                str += tempItems[i] + "\n"; 
            alert(str); 
        }, 
        reverseItems() { 
            this.set("partyItems",  
            this.partyItems.reverseObjects()); 
        }, 
        replaceItems(itemString) { 
            this.partyItems.setObjects( 
            this.helper(itemString)); 
        }, 
        findMultiwordItems() { 
            let reqItem = this.partyItems.reject( 
                (item) => item.split(" ").toArray().length == 1 
            ); 
            alert(reqItem); 
        }, 
    }, 
});

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 Items: </label> 
      {{input value=this.itemString}} 
</div> 
<div> 
    <input
        type="button"
        id="remove-item"
        value="Remove Items"
        {{action "removeItems" this.itemString}} 
      /> 
</div> 
<br /><br /> 
<div> 
    <label>Enter Start Index: </label> 
      {{input value=this.start}} 
</div> 
<div> 
    <label>Enter End Index: </label> 
      {{input value=this.end}} 
</div> 
<div> 
    <input
        type="button"
        id="slice"
        value="Slice"
        {{action "sliceItems" this.start this.end}} 
      /> 
</div> 
<br /><br /> 
<div> 
    <label>Enter Indices: </label> 
      {{input value=this.itemString}} 
</div> 
<div> 
    <input
        type="button"
        id="get-item"
        value="Get Items"
        {{action "getItems" this.itemString}} 
      /> 
</div> 
<br /><br /> 
<div> 
    <label>Enter Items: </label> 
      {{input value=this.itemString}} 
</div> 
<div> 
    <input
        type="button"
        id="replace-item"
        value="Replace Items"
        {{action "replaceItems" this.itemString}} 
      /> 
</div> 
<br /><br /> 
<input
    type="button"
      id="reverse-items"
      value="Reverse"
      {{action "reverseItems"}} 
/> 
<br /><br /> 
<input
    type="button"
      id="find-items"
      value="Find"
      {{action "findMultiwordItems"}} 
/> 
{{outlet}}

输出：访问 localhost:4200/party 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 movie

应用程序/路线/movie.js


import Route from "@ember/routing/route"; 
  
export default class MovieRoute extends Route { 
    movies = [ 
        "The Shawshank Redemption", 
        "The Godfather", 
        "The Dark Knight", 
        "Schindler's List", 
        "The Godfather Part II", 
        "12 Angry Men", 
        "Pulp Fiction ", 
        "Raging Bull", 
        "Parasite", 
        "Se7en", 
        "3 Idiots", 
        "Forrest Gump", 
        "The Green Mile", 
    ]; 
    itemString; 
    itemList; 
    helper(itemString) { 
        this.itemList = itemString.split(","); 
        for (let i = 0; i < this.itemList.length; i++) 
            this.itemList[i] = this.itemList[i].trim(); 
        return this.itemList; 
    } 
    model() { 
        return this.movies; 
    } 
    setupController(controller, model) { 
        super.setupController(controller, model); 
        controller.set("helper", this.helper); 
        controller.set("movies", this.movies); 
        controller.set("itemString", this.itemString); 
        controller.set("itemList", this.itemList); 
    } 
}

应用程序/控制器/movie.js


import Ember from "ember"; 
import { 
    objectsAt, 
    removeObject, 
    removeObjects, 
    setObjects, 
    reject, 
} from "@ember/array"; 
  
export default Ember.Controller.extend({ 
    actions: { 
        getItems(itemString) { 
            this.itemList = this.helper(itemString); 
            for (let i = 0; i < this.itemList.length; i++) 
                this.itemList[i] =  
                    parseInt(this.itemList[i]); 
            let tempItems = this.movies.objectsAt 
                (this.itemList); 
            let str = ""; 
            for (let i = 0; i < tempItems.length; i++) 
                str += tempItems[i] + "\n"; 
            alert(str); 
        }, 
        removeItems(itemString) { 
            this.itemList = this.helper(itemString); 
            if (this.itemList.length == 1) 
                this.movies.removeObject( 
                    this.itemList[0]); 
            else this.movies.removeObjects( 
                this.itemList); 
            this.set("itemString", ""); 
        }, 
        replaceItems(itemString) { 
            this.movies.setObjects(this.helper( 
                itemString)); 
        }, 
        findSingleWordItems() { 
            let reqItem = this.movies.reject( 
                (item) =>  
                    item.split(" ").toArray().length > 1 
            ); 
            alert(reqItem); 
        }, 
    }, 
});

应用程序/模板/movie.hbs


{{page-title "Movie"}} 
<h3>Here is a list of Movies: </h3> 
<ul> 
    {{#each @model as |movie|}} 
        <li>{{movie}}</li> 
      {{/each}} 
</ul> 
<br /><br /> 
<div> 
    <label>Enter Movies: </label> 
      {{input value=this.itemString}} 
</div> 
<div> 
    <input
        type="button"
        id="remove-item"
        value="Remove Movie"
        {{action "removeItems" this.itemString}} 
      /> 
</div> 
<br /><br /> 
<div> 
    <label>Enter Indices: </label> 
      {{input value=this.itemString}} 
</div> 
<div> 
    <input
        type="button"
        id="get-item"
        value="Get Movies"
        {{action "getItems" this.itemString}} 
      /> 
</div> 
<br /><br /> 
<div> 
    <label>Enter Movies: </label> 
      {{input value=this.itemString}} 
</div> 
<div> 
    <input
        type="button"
        id="replace-item"
        value="Replace Movies"
        {{action "replaceItems" this.itemString}} 
      /> 
</div> 
<br /><br /> 
<input
    type="button"
      id="find-items"
      value="Find"
      {{action "findSingleWordItems"}} 
/> 
{{outlet}}

输出：访问 localhost:4200/movie 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 EmberArray objectsAt() 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。