我正在使用 Angular 2 开发应用程序..在我的应用程序中，我使用条形码扫描程序扫描文本字段并将这些项目存储在数组中。 / p>
当我扫描项目时，会添加到数组中，但是当我扫描另一个项目时，旧项目会替换数组中的旧值。
以下是我正在使用的代码段。如果您看到任何针对这个奇怪问题的修复，请帮助我。
import { Component,ViewChild,Input, Output,OnInit,ChangeDetectorRef } from '@angular/core';
import { FormsModule } from '@angular/forms';
import { HeaderComponent } from '../common/header.component';
//import { SaleCart } from '../model/SaleCart';
//import * as $ from "jquery";
declare var jQuery: any
@Component({
selector: 'app-test',
templateUrl: './test.component.html',
styleUrls: ['./posapp.component.css']
})
export class TestComponent implements OnInit{
title = 'Treewalker POS';
public cartItems = [];
public query;
public filteredList = [];
public products = [{"id":"3","name":"Pears Soap Original 75gm","sku":"89675432189","price":"32.00","special_price":"32.00","qty":null,"barcode":"89675432189","tax":"5","discount":"0"},{"id":"1","name":"Rin","sku":"1111111111111","price":"11.00","special_price":"11.00","qty":"10.000","barcode":"1111111111111","tax":"5","discount":"0"},{"id":"2","name":"Test 1","sku":"23456","price":"10.00","special_price":"10.00","qty":"10.000","barcode":"23456","tax":"5","discount":"0"}];
constructor() {
}
ngOnInit() {
}
add(item) {
/* check the items in the json data */
let flag = false;
var foodItem = {};
for (let product of this.products) {
if(product.barcode == item) {
flag = true;
foodItem['ctr'] = 1;
foodItem['item'] = product;
break;
}
}
let localCart = [];
if(sessionStorage.getItem("cart")){
localCart = JSON.parse(sessionStorage.getItem("cart"));
//console.log(JSON.stringify(localCart));
}
//console.log("food "+JSON.stringify(this.cart));
if(flag && localCart.length) {
let exist = 0;
for(let i=0; i < localCart.length; i++) {
if(localCart[i].item.barcode == item) {
localCart[i].ctr = parseInt(localCart[i].ctr) + 1;
//console.log("@@@@ "+this.cart[i].ctr+" --- "+item);
exist = 1;
}
}
if(!exist){
localCart.push(foodItem);
}
sessionStorage.setItem("cart",JSON.stringify(localCart));
//this.barcode = "";
}else if(flag){
localCart.push(foodItem);
sessionStorage.setItem("cart",JSON.stringify(localCart));
}
//this.cart = JSON.parse(sessionStorage.getItem("cart"));
//this.itemsCnt = localCart.length;
//console.log("--- "+this.itemsCnt);
console.log(JSON.parse(sessionStorage.getItem('cart')));
//this.onScanProduct.emit(localCart);
}
filter(e) {
//e.preventDefault();
if (this.query !== ""){
this.filteredList = this.products.filter(function(el){
if(el.barcode.toLowerCase() == this.query.toLowerCase()) {
return el.barcode.toLowerCase() == this.query.toLowerCase();
}else{
return el.barcode.toLowerCase().indexOf(this.query.toLowerCase()) > -1;
}
}.bind(this));
/* scanned item will be added to the cart */
console.log(this.filteredList.length);
if(this.filteredList.length > 0 && e.which == 13){
//console.log(JSON.stringify(this.filteredList));
for (let product of this.filteredList) {
//console.log(filter.barcode+"=="+this.query);
if(product.barcode == this.query) {
this.add(product.barcode);
jQuery('#barcode').val("");jQuery('#barcode').focus();
this.filteredList = [];
}
}
}
}else{
this.filteredList = [];
}
}
}
以下是html模板
<div class="content-wrapper">
<section class="content">
<form>
<div class="row">
<!-- sales item add window -->
<!-- end -->
<div class="col-sm-4">
<div class="box box-primary">
<div class="box-body">
<div class="form-group">
<div class="row">
<div class="col-md-9">
<!--<input type="text" class="form-control" id="barcode" name="barcode" [(ngModel)]="barcode" (ngModelChange)="add($event)"
placeholder="Enter item code or scan the barcode" autocomplete="off" />-->
<input id="barcode" type="text" class="form-control validate filter-input" name="query" [(ngModel)]="query" (keyup)="filter($event)" placeholder="Enter item code or scan the barcode" autocomplete="off" [ngModelOptions]="{standalone: true}">
</div>
<div class="suggestions" *ngIf="filteredList.length > 0">
<ul>
<li *ngFor="let item of filteredList" >
<a (click)="select(item)" href="javascript:;">{{item.barcode}} {{item.name}}</a>
</li>
</ul>
</div>
<div class="col-md-3">
<button type="button" class="btn btn-primary" (click)="createnewproduct(newproduct)">New Product</button>
</div>
</div>
</div>
</div> <!-- end of box body -->
</div>
</div>
</div><!-- end of row -->
</form>
</section>
</div>
以下是用于扫描条形码
的输入字段<input id="barcode" type="text" class="form-control validate filter-input" [(ngModel)]="query" (keyup)="filter()" placeholder="Enter item code or scan the barcode" autocomplete="off">
答案 0 :(得分：0)
我假设你只使用函数add。我尝试在javascript中实现，如下面的代码，但我很确定你在其他地方引用该对象，而你正在改变它。这是我的结论，但我可能错了。
var factoryP = (function(){
function P() {
this.cart = [];
this.products = [{'barcode': 1, 'name': 'a'}, {'barcode': 1, 'name': 'b'}]
}
function add(item) {
/* check the items in the json data */
//console.log("cart length "+JSON.stringify(this.cart));
let flag = false;
var foodItem = {};
for (let product of this.products) {
if(product.barcode == item) {
//console.log("check "+item);
flag = true;
foodItem['ctr'] = 1;
foodItem['item'] = product;
break;
}
}
if(flag && this.cart.length) {
let exist = 0;
for(let i=0; i < this.cart.length; i++) {
if(this.cart[i].item.barcode == item) {
//console.log("Same product");
this.cart[i].ctr = parseInt(this.cart[i].ctr) + 1;
exist = 1;
}
}
if(!exist){
console.log(foodItem);
this.cart.push(foodItem);
}
}else if(flag){
console.log("step 4 "+item);
this.cart.push(foodItem);
}
}
P.prototype.add = add;
return new P();
});
instanceP = factoryP();
instanceP.add(1);
instanceP.add(1);
instanceP.add(1);
instanceP.add(2);
console.log(instanceP.cart[0].ctr)
//output 3
instanceP.cart[1].ctr
//output 1
答案 1 :(得分：0)
在此处查看您的代码。每次使用空数组初始化foodItem数组时。因此，只要代码调用add方法，它就会先清空你的foodItem数组。
请在下面的代码中查看我的评论：
add(item) {
let flag = false;
//Akshay: You need to make your changes here. Initialize your foodItem array out of this scope
var foodItem = {};
for (let product of this.products) {
if(product.barcode == item) {
//console.log("check "+item);
flag = true;
foodItem['ctr'] = 1;
foodItem['item'] = product;
break;
}
}