typescript 打字稿：无法调用类型缺少调用签名的表达式。“号码”类型没有兼容的呼叫签名
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Typescript:Cannot invoke an expression whose type lacks a call signature. Type 'Number' has no compatible call signatures
提问by AConsumer
I know these type of questions are asked before but still it is not clear to me.
我知道以前有人问过这些类型的问题，但我仍然不清楚。
I am a beginner and i was trying to learn import and export in typescript. So i have written the following code. Kindly have a look in to this.
我是初学者，我正在尝试学习打字稿中的导入和导出。所以我写了下面的代码。请看看这个。
I have three files:-
我有三个文件：-
1.animal.ts
2.bird.ts
3.application.ts
Animal.ts:-
动物.ts：-
export class Animal {
name:string
age:number
constructor(name:string,age:number){
this.name=name;
this.age=age
}
sleep(){
console.log("I do sleep")
}
eat(){
console.log("I do eat")
}
}bird.ts
鸟.ts
import {Animal} from "./animal"
export class Bird extends Animal{
constructor(name:string,age:number){
super(name,age)
}
fly(){
console.log("I can fly also")
}
}aplication.ts
应用程序
import { Animal } from "./animal"
import { Bird } from "./bird"
class Application {
constructor() {
console.log("Hi i am a bird !!")
}
}
var animal = new Animal("Rhino", 10);
var bird = new Bird("Pigeon", 3)
animal.age(); //Cannot invoke an expression whose type lacks a call signature. Type 'Number' has no compatible call signatures
animal.name(); //Cannot invoke an expression whose type lacks a call signature. Type 'String' has no compatible call signatures.
bird.age(); //Cannot invoke an expression whose type lacks a call signature. Type 'Number' has no compatible call signatures
bird.fly();
bird.sleep();How do i solve this problem ? and what this error actually means ?
我如何解决这个问题？这个错误实际上意味着什么？
回答by kctang
bird.age()does not work because it is a number. console.log(bird.age)will work.
bird.age()不起作用，因为它是一个数字。console.log(bird.age)将工作。
bird.fly()works because it is a function.
bird.fly()有效，因为它是一个函数。
Similar pattern for all other issues.
所有其他问题的类似模式。
回答by kabanus
Your problem is not with imports or exports, that looks OK. This:
您的问题不在于导入或导出，看起来没问题。这个：
Cannot invoke an expression whose type lacks a call signature. Type 'Number' has no compatible call signatures
says it all. You use age(), so you are using age as if it is a function (has a call signature). But age is a number - you can add it, print it, etc., but you can't "call" it. That's why the other lines don't fail - You can call them properly.
都说了。您使用age()，因此您使用 age 就好像它是一个函数（具有调用签名）。但年龄是一个数字——你可以添加、打印它等，但你不能“调用”它。这就是其他线路不会失败的原因 - 您可以正确调用它们。
回答by AhammadaliPK
This error will also happen when you tried to access a property of a class with parenthesis . For example you have created a property in a class like ,
当您尝试访问带有括号的类的属性时，也会发生此错误。例如，您在类中创建了一个属性，例如，
private get printTemplateDetailsUrl(): string {
return `${this._baseHref}://getUserPrintTemplateDetailsJson`;
}
and you have tried to access that property like this ,
并且您尝试像这样访问该属性，
let url = this.printTemplateDetailsUrl();
so it will give an error as ,
所以它会给出一个错误，
Cannot invoke an expression whose type lacks a call signature. Type 'String' has no compatible call signatures
so if you want to access that property , you don't need trailing parenthesis , you can access like this ,
所以如果你想访问那个属性，你不需要尾括号，你可以这样访问，
let url = this.printTemplateDetailsUrl;
