javascript - TypeError : . currentPizzaPlace.getPoint 不是函数

Question

类型错误:this.pizzaPlaceEditService.currentPizzaPlace.getPoint 不是函数

我找到了TypeError: is not a function typescript class但我认为这不适用于这种情况。又发现了几个似乎不适用的。这是我编辑过的类(class):

export class PizzaPlace {
  deliveryArea = [];

  getPoint(seq: number): Point {
    let result: Point = null;

    this.deliveryArea.forEach(function(point:Point) {
      if(seq == point.sequence) {
        result = point;
      }
    });

    return result;
  }

}

这是我的工作单元测试:

  it('should retrieve a point by sequence', () => {
    var point1 = new Point();
    point1.sequence = 0;
    point1.latitude = 5.12;
    point1.longitude = 5.12;

    var point2 = new Point();
    point2.sequence = 1;
    point2.latitude = 6.13;
    point2.longitude = 6.13;

    var point3 = new Point();
    point3.sequence = 2;
    point3.latitude = 5.25;
    point3.longitude = 5.25;

    pizzaPlace.deliveryArea = [point1, point2, point3];

    expect(pizzaPlace.getPoint(0)).toBe(point1);
    expect(pizzaPlace.getPoint(1)).toBe(point2);
    expect(pizzaPlace.getPoint(2)).toBe(point3);
    expect(pizzaPlace.getPoint(3)).toBe(null);
  });

这是生成错误的代码:

  onDownClick(): void {
    if(this.selectedPoint) {
      let currSeq = this.selectedPoint.sequence;
      let nextSeq = currSeq + 1;
      console.log("Current pizza place:" + JSON.stringify(this.pizzaPlaceEditService.currentPizzaPlace));
      console.log("nextSeq:" + nextSeq);
      let next = this.pizzaPlaceEditService.currentPizzaPlace.getPoint(nextSeq);
      if(next) {
        this.pizzaPlaceEditService.currentPizzaPlace.swapPoints(this.selectedPoint, next);
      }
    }
  }

这是错误:

Current pizza place:{"contactName":"Zaphod Beeblebrox","customerId":"TPGup2lt","deliveryArea":[{"errorMsg":"","sequence":0,"latitude":34.552,"longitude":-84.556},{"errorMsg":"","sequence":1,"latitude":34.711,"longitude":-84.665}],"deliveryZips":[],"paypalAccount":"HB17","settings":null,"shopName":"Donato's Hartland","shopStreet":"1531 Kenesaw Dr","shopCity":"Lexington","shopState":"KY","shopZip":"40515","shopPhone":"(859)555-2637","billStreet":"1531 Kenesaw Dr","billCity":"Lexington","billState":"KY","billZip":"40515","billPhone":"(859)555-2637"}
pizza-place-delivery.component.ts:63:6
nextSeq:1
pizza-place-delivery.component.ts:64:6
TypeError: this.pizzaPlaceEditService.currentPizzaPlace.getPoint is not a function

我已经没有什么可以尝试的了。任何建议表示赞赏!

Answer 1

感谢 Artem 的出色输入，我能够弄清楚问题是由于我从 JSON 创建对象而不是我想要的对象而引起的，因此它是不同的类型。显然，Typescript 中的类仅在编译时存在，并在运行时被丢弃。

因此，基于:How do I initialize a TypeScript object with a JSON object所选答案的选项4，我创建了一个serialized.ts。

export interface Serializable<T> {
  deserialize(input: Object): T;
}

然后用实现修改我的类:

export class PizzaPlace implements Serializable<PizzaPlace> {

然后添加:

  deserialize(input): PizzaPlace {
    this.paypalAccount = input.paypalAccount;
    this.customerId = input.customerId;
    ...
    this.settings = input.settings;

    return this;
  }

然后，由于我的网络服务返回了这些数组，我更改了我的服务调用:

  .subscribe(places => this.deserializePlaces(places));

并添加了一个新功能:

  deserializePlaces(places: Object[]){
    this.pizzaPlaces = [];

    places.forEach(obj=> {
      let place = new PizzaPlace().deserialize(obj);
      this.pizzaPlaces.push(place);
    });
  }

这似乎工作得很好。感谢您的投入。