Embeer.js EmberArray objectsAt()用法及代碼示例

Ember.js 是一個開源 JavaScript 框架，用於開發基於 Model-View-Controller (MVC) 架構的大型客戶端 Web 應用程序。 Ember.js是使用最廣泛的前端應用框架之一。它的目的是加速開發並提高生產力。目前，它被大量網站使用，包括 Square、Discourse、Groupon、Linked In、Live Nation、Twitch 和 Chipotle。

objectsAt() 方法用於獲取給定索引數組的項目。

用法:

objectsAt(indexes)

參數：

indexes: 需要獲取對象的索引。

返回：退回的物品。

安裝和運行 Ember.js 的步驟：

第 1 步：要運行以下示例，您需要有一個 ember 項目。要創建一個，您需要先安裝ember-cli。在終端中寫入以下代碼：

npm install ember-cli

第 2 步：現在您可以通過輸入以下代碼來創建項目：

ember new <project-name> --lang en

要啟動服務器，請鍵入：

ember serve

示例 1：鍵入以下代碼以生成本示例的路由：

ember generate route party

應用程序/路線/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); 
    } 
}

應用程序/控製器/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); 
        }, 
    }, 
});

應用程序/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}}

輸出：訪問 localhost:4200/party 查看輸出

示例 2：鍵入以下代碼以生成本示例的路由：

ember generate route movie

應用程序/路線/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); 
    } 
}

應用程序/控製器/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); 
        }, 
    }, 
});

應用程序/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}}

輸出：訪問 localhost:4200/movie 查看輸出

參考： https://api.emberjs.com/ember/4.4/classes/MutableArray/methods

相關用法

注：本文由純淨天空篩選整理自aayushmohansinha大神的英文原創作品 Ember.js EmberArray objectsAt() Method。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。