Embeer.js Ember.NativeArray unshiftObject()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。

unshiftObject() 方法用于将单个对象添加到数组的开头。

用法:

unshiftObject(obj)

参数：

obj: 要添加的对象。

返回值：新的数组。

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', 
    ]; 
    item; 
    itemString; 
    itemList; 
    start; 
    end; 
    idx; 
    model() { 
        return this.partyItems; 
    } 
    setupController(controller, model) { 
        this._super(controller, model); 
        controller.set('partyItems', this.partyItems); 
        controller.set('item', this.item); 
        controller.set('itemString', this.itemString); 
        controller.set('itemList', this.itemList); 
        controller.set('start', this.start); 
        controller.set('end', this.end); 
        controller.set('idx', this.idx); 
    } 
}

应用程序/控制器/party.js


import Ember from 'ember'; 
import { 
    without, toArray, unshiftObject, unshiftObjects, 
    removeAt, objectAt, find, replace, uniq 
} 
    from '@ember/array'; 
  
export default Ember.Controller.extend({ 
    actions: { 
        withoutItem(item) { 
            console.log(item) 
            let tempItems; 
            tempItems = this.partyItems.without(item); 
            let str = ''; 
            for (let i = 0; i < tempItems.length; i++) 
                str += tempItems[i] + '\n'; 
            alert(str); 
            this.set('item', ''); 
        }, 
        addItems(itemString) { 
            this.itemList = itemString.split(',').toArray(); 
            if (this.itemList.length == 1) 
                this.partyItems.unshiftObject(this.itemList[0]); 
            else
                this.partyItems.unshiftObjects(this.itemList); 
            this.set('itemString', ''); 
        }, 
        removeItems(start, end) { 
            this.partyItems.removeAt(start, end); 
        }, 
        getObject(idx) { 
            alert(`The item at index ${idx} is  
            ${this.partyItems.objectAt(idx)}`); 
        }, 
        findMultipleWordItems() { 
            let reqItem = this.partyItems.find((item) => 
                item.split(' ').toArray().length > 1); 
            alert(reqItem); 
        }, 
        replaceItem(itemString) { 
            this.itemList = itemString.split(',').toArray(); 
            if (this.itemList.length > this.partyItems.length) 
                alert('Error'); 
            this.partyItems.replace(0, this.itemList.length, 
                this.itemList); 
        }, 
        getUniqueItems() { 
            let tempItems = this.partyItems.uniq(); 
            let str = ''; 
            for (let i = 0; i < tempItems.length; i++) 
                str += tempItems[i] + '\n'; 
            alert(str); 
            this.set('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> 
    <input
        type="button"
        id="remove-item"
        value="Remove Item"
        {{action "withoutItem" this.item}} 
      /> 
</div> 
<br /><br /> 
<div> 
    <label>Enter Items: </label> 
      {{input value=this.itemString}} 
</div> 
<div> 
    <input
        type="button"
        id="add-item"
        value="Add Items"
        {{action "addItems" 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="remove-items"
        value="Remove Items"
        {{action "removeItems" this.start this.end}} 
      /> 
</div> 
<br /><br /> 
<div> 
    <label>Enter Index: </label> 
      {{input value=this.idx}} 
</div> 
<div> 
    <input
        type="button"
        id="get-item"
        value="Get Item"
        {{action "getObject" this.idx}} 
      /> 
</div> 
<br /><br /> 
<div> 
    <label>Enter Items: </label> 
      {{input value=this.itemString}} 
</div> 
<div> 
    <input
        type="button"
        id="replace-item"
        value="Replace Items"
        {{action "replaceItem" this.itemString}} 
      /> 
</div> 
<br /><br /> 
<input
    type="button"
      id="get-multiword"
      value="Get Multiword Items!"
      {{action "findMultipleWordItems"}} 
/> 
<br /><br /> 
<input
    type="button"
      id="get-unique"
      value="Get Unique Items!"
      {{action "getUniqueItems"}} 
/> 
{{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 notepad

应用程序/路线/notepad.js


import Route from '@ember/routing/route'; 
  
export default class NotepadRoute extends Route { 
    items = []; 
    item; 
    model() { 
        return this.items; 
    } 
    setupController(controller, model) { 
        super.setupController(controller, model); 
        controller.set('items', this.items); 
    } 
}

应用程序/控制器/notepad.js


import Ember from 'ember'; 
import { pushObject } from '@ember/array'; 
  
export default Ember.Controller.extend({ 
    actions: { 
        withoutItem(item) { 
            let tempItems; 
            tempItems = this.items.without(item); 
            let str = ''; 
            for (let i = 0; i < tempItems.length; i++) 
                str += tempItems[i] + '\n'; 
            alert(str); 
            this.set('item', ''); 
        }, 
        replaceItem(item) { 
            let itemList = item.split(',').toArray(); 
            if (itemList.length > this.items.length) 
                alert('Error'); 
            this.items.replace(0, itemList.length, itemList); 
        }, 
        addItem(item) { 
            this.items.unshiftObject(item); 
        }, 
        getUniqueItems() { 
            let tempItems = this.items.uniq(); 
            let str = ''; 
            for (let i = 0; i < tempItems.length; i++) 
                str += tempItems[i] + '\n'; 
            alert(str); 
            this.set('item', ''); 
        }, 
    }, 
});

应用程序/模板/notepad.hbs


{{page-title "Notepad"}} 
<h2>Notepad</h2> 
<div> 
    <label>Enter Item: </label> 
      {{input value=this.item}} 
</div> 
<div> 
    <input
        type="button"
        id="add-item"
        value="Add Item"
        {{action "addItem" this.item}} 
      /> 
</div> 
<br /><br /> 
<ul> 
    {{#each @model as |item|}} 
        <li>{{item}}</li> 
      {{/each}} 
</ul> 
<br /><br /> 
<div> 
    <label>Enter Item: </label> 
      {{input value=this.item}} 
</div> 
<div> 
    <input
        type="button"
        id="without-item"
        value="Without Item"
        {{action "withoutItem" this.item}} 
      /> 
</div> 
<br /><br /> 
<div> 
    <label>Enter Item: </label> 
      {{input value=this.item}} 
</div> 
<div> 
    <input
        type="button"
        id="replace-item"
        value="Replace Item"
        {{action "replaceItem" this.item}} 
      /> 
</div> 
<br /><br /> 
<input
    type="button"
      id="get-unique"
      value="Get Unique Items!"
      {{action "getUniqueItems"}} 
/> 
{{outlet}}

输出：访问 localhost:4200/notepad 查看输出

参考：https://api.emberjs.com/ember/4.6/classes/Ember.NativeArray/methods

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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 Ember.NativeArray unshiftObject() 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。