typescript 打字稿匿名类
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Typescript anonymous class
提问by user1137582
Is there a way in typescript to create anonymous class?
打字稿中有没有办法创建匿名类？
my code:
我的代码：
export abstract class Runnable {
public abstract run();
}
and I'm trying to do something like this:
我正在尝试做这样的事情：
new Runnable {
runner() {
//implement
}
}
How can I do it?
我该怎么做？
回答by Nitzan Tomer
Not quite, but you can do this:
不完全是，但你可以这样做：
abstract class Runnable {
public abstract run();
}
let runnable = new (class MyRunnable extends Runnable {
run() {
console.log("running...");
}
})();
runnable.run(); // running...
（操场上的代码）
The problem with this approach however is that the interpreter will evaluate the class every time it uses it, unlike with a compiled language (such as java) in which the compiler only evaluates it once.
然而，这种方法的问题在于，解释器每次使用类时都会对其进行评估，这与编译器只对其进行一次评估的编译语言（例如 java）不同。
回答by Michal
Yes, here is the way.
是的，这就是方法。
The abstract class:
抽象类：
export abstract class Runnable {
public abstract run();
}
An anonymous implementation:
匿名实现：
const runnable = new class extends Runnable {
run() {
// implement here
}
}();
回答by holi-java
How to create Anonymous Class?
如何创建匿名类？
Let's say you have a interface Runnableand an abstract class Task.when you declare a class Fooin typescript you actual create an class instance of Foo& a constructor function for the class Foo.you could want to see depth in typescript.Anonymous class that ref as a constructor function like {new(...args):type}that can be created using newkeyword.
比方说，你有一个接口Runnable和抽象类Task。当你声明一个类Foo的打字稿你实际创建的类实例Foo及该类的构造函数Foo。你可能希望看到深度打字稿.Anonymous类，裁判的构造函数像{new(...args):type}这样可以使用new关键字创建。
interface Runnable {
run(): void;
}
abstract class Task {
constructor(readonly name: string) {
}
abstract run(): void;
}
Create anonymous class extends superclass via class extends ?
通过创建匿名类扩展超类 class extends ?
test('anonymous class extends superclass by `class extends ?`', () => {
let stub = jest.fn();
let AntTask: {new(name: string): Task} = class extends Task {
//anonymous class auto inherit its superclass constructor if you don't declare a constructor here.
run() {
stub();
}
};
let antTask: Task = new AntTask("ant");
antTask.run();
expect(stub).toHaveBeenCalled();
expect(antTask instanceof Task).toBe(true);
expect(antTask.name).toBe("ant");
});
create anonymous class implements interface/type via class ?.
创建匿名类通过class ?.
test('anonymous class implements interface by `class ?`', () => {
let stub = jest.fn();
let TestRunner: {new(): Runnable} = class {
run = stub
};
let runner: Runnable = new TestRunner();
runner.run();
expect(stub).toHaveBeenCalled();
});
