TypeScript is a strict superset of JavaScript that adds optional static typing and classes to the language without limiting JavaScript functionality. It allows for compile-time checking of code and outputs plain JavaScript that runs on any browser or JavaScript engine. TypeScript supports classes, modules, interfaces and other features to help organize large applications, while also allowing for optional type annotations that enable type checking and catch errors.

1. THE JS SUPERSET

2. What?
A Strict superset of JavaScript.
Outputs plain JavaScript
Works on all JavaScript engines
It transpiles to JavaScript

3. Why ?
JavaScript is BROKEN !!!!
Allows compile checking of code.
JavaScript compatible with IE 8 and up.
Offers classes, modules and interfaces.
Basic auto-complete
Open source project, Managed my Microsoft.
Optionally typed

4. Why Not?
Slows down compile slightly.
Integrating third party libraries.

5. How ?
To install
Run the following in npm:
Or
in Visual Studio 2013 just install as extention.
(Already in VS 2015)
npm install -g typescript
To Use
Run: script.ts -> script.js
Or
Grunt
typescript: {
all: {
src: ["Scripts/typings/**/*.ts", "www/app/*.ts", "www/app/**/*.ts"],
dest: "www/scripts/appbundle.js",
options: {
sourceMap: true,
declaration: false,
removeComments: true,
noEmitOnError: true,
target: 'ES5',
}
}

6. Typescript Class
http://www.typescriptlang.org/Playground
class Greeter {
greeting: string;
constructor(message: string) {
this.greeting = message;
}
greet() {
return "Hello, " + this.greeting;
}
}
var Greeter = (function () {
function Greeter(message) {
this.greeting = message;
}
Greeter.prototype.greet = function () {
return "Hello, " + this.greeting;
};
return Greeter;
})();

7. Typescript Module(Namespaces)
module Sayings {
export class Greeter {
greeting: string;
constructor(message: string) {
this.greeting = message;
}
greet() {
return "Hello, " +
this.greeting;
}
}
}
var greeter = new
Sayings.Greeter("world");
var Sayings;
(function (Sayings) {
var Greeter = (function () {
function Greeter(message) {
this.greeting = message;
}
Greeter.prototype.greet = function () {
return "Hello, " + this.greeting;
};
return Greeter;
})();
Sayings.Greeter = Greeter;
})(Sayings || (Sayings = {}));
var greeter = new Sayings.Greeter("world");

8. Typescript Generic
class Greeter<T> {
greeting: T;
constructor(message: T) {
this.greeting = message;
}
greet() {
return this.greeting;
}
}
var Greeter = (function () {
function Greeter(message) {
this.greeting = message;
}
Greeter.prototype.greet = function () {
return this.greeting;
};
return Greeter;
})();

9. Other functions
Mixins
Inheritance
Enumerated type
Play on: http://www.typescriptlang.org/Playground

10. Other solutions