TypeScript

http://www.typescriptlang.org/

TypeScript offers classes, modules, and interfaces to help you build robust components.

These features are available at development time for high-confidence application development, but are compiled into simple JavaScript.

TypeScript types let you define interfaces between software components and to gain insight into the behavior of existing JavaScript libraries.

Install

sudo npm install -g typescript

First program

cat > inheritance.ts

class Animal {
    constructor(public name: string) { }
    move(meters: number) {
        alert(this.name + " moved " + meters + "m.");
    }
}

class Snake extends Animal {
    constructor(name: string) { super(name); }
    move() {
        alert("Slithering...");
        super.move(5);
    }
}

class Horse extends Animal {
    constructor(name: string) { super(name); }
    move() {
        alert("Galloping...");
        super.move(45);
    }
}

var sam = new Snake("Sammy the Python");
var tom: Animal = new Horse("Tommy the Palomino");

sam.move();
tom.move(34);

tsc inheritance.ts