Angular 5和Priming下拉列表动态添加和删除选项

我研究角度5和打底。我的项目页面有两个p下拉列表，要求是，如果汽车下拉列表中的标签是“其他”，则在第二个下拉列表中添加一个名为“无油漆”的选项，如果汽车下拉列表标签不是“Ohters”，则从第二个下拉列表中删除“无油漆”选项。我一直在动态地添加和删除下拉选项。请大家指点一下，下面是我的代码。谢谢

    Car: <p-dropdown [options]="cars" [(ngModel)]="selectedCar" [filter]="true"></p-dropdown>

    <p-dropdown [options]="paints" [(ngModel)]="selectedPaint" [filter]="true"></p-dropdown>

    constructor() {
            this.cars= [
                {name: 'AA', code: 'aa'},
                {name: 'BB', code: 'bb'},
                {name: 'CC', code: 'cc'},
                {name: 'DD', code: 'dd'},
                {name: 'Others', code: 'others'}
            ];

this.paints= [
                {name: 'XX', code: 'xx'},
                {name: 'YY', code: yyb'},
                {name: 'ZZ', code: 'zz'}
            ];

---

我确实尝试过这个.cars.pushnew下拉选项'Others'，'Others'，但这是添加'Others'选项的次数与我更改下拉值的次数一样多。

这应该很简单。更改后添加第一个p下拉式车辆事件

---

我使用ES6完成了以下工作：

if(event.value.code === 'others'){
this.paints.find(paint => paint.code == 'No Paint') === undefined ? this.paints.push({name:'No paint', code: 'No Paint'}) : null;
}
else{
this.paints = this.paints.filter(e => e !== 'Others') //remove 'Others'
}

---

请创建stackblitzlink@Justcode很抱歉，它在我的组织中被阻止。请尝试任何在线创建者，然后尝试codpen

<p-dropdown [options]="cars" 
(onChange)="checkIfOther($event)" 
[(ngModel)]="selectedCar" 
[filter]="true"></p-dropdown>

checkIfOther(event){
if(event.value.code === 'others'){
this.paints.find(paint => paint.code == 'No Paint') === undefined ? this.paints.push({name:'No paint', code: 'No Paint'}) : null;
}
else{
let idx = this.paints.findIndex(paint => paint.code == 'No Paint';
idx != undefined ? this.paints.slice(idx,1) : null;
}

if(event.value.code === 'others'){
this.paints.find(paint => paint.code == 'No Paint') === undefined ? this.paints.push({name:'No paint', code: 'No Paint'}) : null;
}
else{
this.paints = this.paints.filter(e => e !== 'Others') //remove 'Others'
}