Angular 19：“WritableSignal”类型上不存在属性“mutate”<Vehicle>

Question

我正在使用 Angular 19 并尝试使用 mutate 方法和包含车辆对象的信号。但是，我遇到以下错误：

Property 'mutate' does not exist on type 'WritableSignal<Vehicle>'. 这是我的代码片段：

import { Component, signal, computed, effect } from '@angular/core';
import { bootstrapApplication } from '@angular/platform-browser';
import { FormsModule } from '@angular/forms';

export interface Vehicle {
  id: number;
  name: string;
  price: number;
}

@Component({
  selector: 'app-root',
  imports: [FormsModule],
  template: `
    <h1>{{ quantity() }}</h1>
    <select [ngModel]="quantity()" (change)="onSelectQ($event)">
      <option *ngFor="let x of quantityArr()">{{ x }}</option>
    </select>
    <div>Vehicle: {{ selectedVehicle().name }}</div>
    <div>Vehicle Price: {{ selectedVehicle().price }}</div>
    <div>Total: {{ exPrice() }}</div>
  `,
})
export class App {
  quantity = signal<number>(1);
  quantityArr = signal<number[]>([1, 2, 3, 4, 5, 6, 7, 8, 9]);
  vehicles = signal<Vehicle[]>([
    { id: 1, name: 'Lexus', price: 100 },
    { id: 2, name: 'Zen', price: 200 },
    { id: 3, name: 'Duster', price: 300 },
  ]);
  selectedVehicle = signal<Vehicle>(this.vehicles()[0]);

  exPrice = computed(() => this.selectedVehicle().price * this.quantity());

  constructor() {
    // Trying to use mutate here:
    this.selectedVehicle.mutate((v: Vehicle) => (v.price = v.price * 1.2));
  }

  quantityEffect = effect(() => {
    console.log(this.quantity());
  });

  onSelectQ(event: any) {
    this.quantity.set(Number(event.target.value));
  }
}

bootstrapApplication(App);

package.json

{
  "dependencies": {
    "@angular/core": "^19.0.0",
    "@angular/forms": "^19.0.0",
    "@angular/platform-browser": "^19.0.0",
    "rxjs": "^7.8.1",
    "zone.js": "~0.15.0"
  },
  "devDependencies": {
    "@angular/cli": "^19.0.0",
    "@angular/compiler-cli": "^19.0.0",
    "typescript": "^5.6.3"
  }
}

为什么 Angular 19 的 mutate 方法不适用于 WritableSignal

？在 Angular 中更新信号对象属性的正确方法是什么？

这是视频参考

我正在学习版本 19 的角度信号，我正在关注下面的视频

https://www.youtube.com/watch?v=oqYQG7QMdzw&list=PLErOmyzRKOCr07Kcnx75Aqh6PWSbIokPB&index=1

Answer 1

mutate

方法已在v18中删除，因此此后不再可用。

该视频有点过时了。

如果你想改变信号，你要么依赖

set

或

update

方法。