Typescript: Declare functions without implementing them

问题

Is it possible to declare that a class has certain functions without implementing them?

I need this because I create a class that is then passed to a js framework which adds a couple of functions. I wanna be able to call those functions aswell without reimplementing them, redirecting or casting or whatsoever.

Example:

//example class
class AppComponent {
   constructor() {}
}

//create class
var comp: AppComponent = new AppComponent();

//hand over to framework
fw.define("Component", comp);

//now I want to be able to call the added functions such as:
comp.setModel(/*some model*/);

回答1:

You may declare the function without implementing it.

//example class
class AppComponent {
    constructor() { }
    setModel: () => void;
}

//create class
var comp: AppComponent = new AppComponent();

//hand over to framework
fw.define("Component", comp);

//now I want to be able to call the added functions such as:
comp.setModel(/*some model*/);

来源：https://stackoverflow.com/questions/44653623/typescript-declare-functions-without-implementing-them