Angular 5模型httpClient类型转换 [英] Angular 5 models httpClient type casting

问题描述

我在Ingredient.model.ts中声明了一个模型

I declare a model in ingredient.model.ts

export class Ingredient {
 constructor(private name: string, public amount: number) {}

 getName() { return this.name }
}

如果我以这种方式获取它们，则在Ingredients.service.ts中:

In ingredients.service.ts, if I get them in this way:

httpClient.get<Ingredient>(url).subscribe(
 (igredient) => {
   console.log(igredient.getName());
 });

它在控制台中产生错误，例如属性igredient中没有方法getName".

It gives errors in console, such as "no method getName in property igredient".

此外，每当我尝试声明属性类型Category []时，它都会失败，但是Array似乎工作正常.

Also, whenever I try to declare a property type Category[] it fails, but Array seems working fine.

修改: 我想提供更多信息.

I want to provide more info.

给出Igredient模型和以下JSON结构:

Given the Igredient model and the following JSON structure:

{
 name: "Apple",
 amount: "5",
 created_at: "date",
}

甚至没有调用Igredient构造函数，因此不会解析GET有效负载.

The Igredient constructor isn't even invoked, therefore the GET payload won't be parsed.

推荐答案

您需要使用属性，而不是方法.返回的对象实际上是一个json对象，没有"getName()"方法之类的东西(尽管您努力添加类型信息).尝试这样的事情:

You'll need to use a property, not a method. The returned object is really a json object, and there is no such thing as "getName()" method (despite your effort to add a type information). Try something like this:

export interface Ingredient {
    strin: string,
    amount: number,
    created_at: string
}


httpClient.get<Ingredient>(url).subscribe(
     (igredient) => {
          console.log(igredient.amount);
});

您需要根据预期的json对象提供类型信息.如果返回的json对象具有属性，strin，amount和created_at，则需要定义与预期的json对象兼容的类型.

You need to provide a type information based on the expected json object. If the returned json object has attributes, strin, amount, and created_at, then you need to define a type that is compatible with the expected json object.

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