Is it possible to use getters/setters in interface definition?

Question

At the moment, TypeScript does not allow use get/set methods(accessors) in interfaces. For example:

interface I {
      get name():string;
}

cl         


        

Answer 1

First of all, Typescript only supports get and set syntax when targetting Ecmascript 5. To achieve this, you have to call the compiler with

tsc --target ES5

Interfaces do not support getters and setters. To get your code to compile you would have to change it to

interface I { 
    getName():string;
}

class C implements I { 
    getName():string {
          return null;
    }   
}

What typescript does support is a special syntax for fields in constructors. In your case, you could have

interface I {
    getName():string;
}

class C implements I {
    constructor(public name: string) {
    }
    getName():string {
        return name;
    }
}

Notice how class C does not specify the field name. It is actually declared using syntactic sugar public name: string in the constructor.

As Sohnee points out, the interface is actually supposed to hide any implementation details. In my example, I have chosen the interface to require a java-style getter method. However, you can also a property and then let the class decide how to implement the interface.