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Embeer.js EmberObject decrementProperty()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。

decrementProperty() 方法用於將屬性的值設置為當前值減去某個值。

用法:

decrementProperty(keyName,decrement);

參數：

  • keyName: 它是我們要減少其值的屬性的名稱。
  • decrement:這是我們想要減少到的值。默認值為 1。

返回值：此方法返回一個新的屬性值。

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 decrement1

應用程序/路線/decrement1.js

Javascript


import Route from '@ember/routing/route';
import EmberObject from '@ember/object';
import { } from '@ember/array';
export default class FruitsRoute extends Route {
    students = [
        EmberObject.create(
            { name: 'Rahul', Class: 11, marks: 75 }),
        EmberObject.create(
            { name: 'Sam', Class: 12, marks: 59 }),
        EmberObject.create(
            { name: 'David', Class: 11, marks: 67 }),
        EmberObject.create(
            { name: 'Druv', Class: 12, marks: 44 }),
        EmberObject.create(
            { name: 'Mahan', Class: 12, marks: 87 }),
        EmberObject.create(
            { name: 'Ram', Class: 11, marks: 71 }),
        EmberObject.create(
            { name: 'Dadu', Class: 12, marks: 58 })
    ];
    model() {
        return this.students;
    }
    setupController(controller, model) {
        super.setupController(controller, model);
        controller.set('students', this.students);
    }
}

應用程序/控製器/decrement1.js

Javascript


import Ember from "ember";
import { isAny, isEvery } from "@ember/array";
export default Ember.Controller.extend({
    actions: {
        increase(data) {
            this.students.forEach((item) => 
            item.incrementProperty('marks', JSON.parse(data)));
        },
        decrease(data) {
            this.students.forEach((item) => 
            item.decrementProperty('marks', JSON.parse(data)));
        },
        remove(item) {
            this.students.set('[]', 
            this.students.without(this.students.
            findBy('name', item)));
        },
        show_first() {
            let ans = this.students.get('firstObject');
            alert(ans.name)
        },
        show_last() {
            let ans = this.students.get('lastObject');
            alert(ans.name)
        },
    },
});

應用程序/模板/decrement1.hbs

Javascript


{{page-title "decrementProperty"}}
<h3>Students List: </h3>
<table>
    <tr>
        <th>Name</th>
        <th>Class</th>
        <th>Marks</th>
    </tr>
    {{#each @model as |detail|}}
        <tr>
            <td>{{detail.name}}</td>
            <td>{{detail.Class}}</td>
            <td>{{detail.marks}}</td>
        </tr>
    {{/each}}
</table>
<br />
<div>
    <label>Enter value: </label>
    {{input value=this.item}}
</div>
<input
    type="button"
    id="increase-marks"
    value="Increase All marks by Value"
    {{action "increase" this.item}}
/>
<br /><br />
<div>
    <label>Enter value: </label>
    {{input value=this.item2}}
</div>
<input
    type="button"
    id="decrease-marks"
    value="decrease All marks by Value"
    {{action "decrease" this.item2}}
/>
<br /><br />
<div>
    <label>Enter Name: </label>
    {{input value=this.item3}}
</div>
<input
    type="button"
    id="remove-student"
    value="Remove Student"
    {{action "remove" this.item3}}
/>
<br /><br />
<input
    type="button"
    id="first-student"
    value="Show First Student in list"
    {{action "show_first"}}
/>
<br /><br />
<input
    type="button"
    id="last-student"
    value="Show Last Student in list"
    {{action "show_last"}}
/>
{{outlet}}

輸出：訪問 localhost:4200/decrement1 查看輸出

Ember.js EmberObject decrementProperty() 方法

示例 2：鍵入以下代碼以生成本示例的路由：

ember generate route decrement2

應用程序/路線/decrement2.js

Javascript


import Route from '@ember/routing/route';
import EmberObject from '@ember/object';
export default class WebsitesRoute extends Route {
    food = [
        EmberObject.create({
            food: 'apple',
            isFruit: true,
            quant: 3,
        }),
        EmberObject.create({
            food: 'Potato',
            isFruit: false,
            quant: 4,
        }),
        EmberObject.create({
            food: 'Banana',
            isFruit: true,
            quant: 2,
        }),
        EmberObject.create({
            food: 'Burgur',
            isFruit: false,
            quant: 2,
        }),
        EmberObject.create({
            food: 'Orange',
            isFruit: true,
            quant: 7,
        }),
    ];
    temp;
    model() {
        return this.food;
    }
    setupController(controller, model) {
        super.setupController(controller, model);
        controller.set('food', this.food);
        controller.set('temp', this.temp);
        controller.set('food2', this.food2);
    }
}

應用程序/控製器/decrement2.js

Javascript


import Ember from 'ember';
export default Ember.Controller.extend({
    value: 0,
    actions: {
        remove_item(item) {
            this.food.set('[]', 
            this.food.without(this.food.findBy('food', item)));
        },
        list() {
            let ans = '';
            this.food.forEach((item) => 
            ans += item.get('food') + '\n');
            alert(ans)
        },
        increase() {
            this.food.forEach((item) => 
            item.incrementProperty('quant'));
        },
        decrease() {
            this.food.forEach((item) => 
            item.decrementProperty('quant'));
        },
    },
});

應用程序/模板/decrement2.hbs

Javascript


{{page-title "decrementProperty"}}
<h3>List of Item in Buckets</h3>
<table>
    <tr>
        <th> Food_Name </th>
        <th>Bucket </th>
        <th>Fruit </th>
    </tr>
    {{#each @model as |website|}}
        <tr>
            <td>{{website.food}}</td>
            <td>{{website.quant}}</td>
            <td>{{website.isFruit}}</td>
        </tr>
    {{/each}}
</table>
<br />
<div>
    <label>Enter value: </label>
    {{input value=this.item}}
</div>
<input
    type="button"
    id="R-item"
    value="Remove this item"
    {{action "remove_item" this.item}}
/>
<br /><br />
<input type="button" id="list-items"
       value="List All Items"
       {{action "list"}} />
<br /><br />
<input
    type="button"
    id="increase-property"
    value="Increase Quantity"
    {{action "increase"}}
/>
<br /><br />
<input
    type="button"
    id="decrease-property"
    value="decrease Quantity"
    {{action "decrease"}}
/>
{{outlet}}

輸出：訪問 localhost:4200/decrement2 查看輸出

Ember.js EmberObject decrementProperty() 方法

參考： https://api.emberjs.com/ember/4.4/classes/EmberObject/methods/decrementProperty?anchor=decrementProperty



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注：本文由純淨天空篩選整理自akki_07大神的英文原創作品 Ember.js EmberObject decrementProperty() 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。