TypeScript - Keywords

as: Use the as keyword to give an exported class an alias. You can export ClassA as ClassB and it will appear as ClassB in the classes in which import into.

export Employee as StaffMember;

const: Values cannot be changed once they are bound. A const can be used anywhere.

const secretCode: string = "abc";

export: Allows you to convert and encapsulate your code into a "module" making it available to other ts code which will them import it. Very much like namespaces.

export class Spaceship{}

Extends: Used with Abstract Classes and derived Classes. A derived Class extends an abstract class.

class Dog extends Animal

Implements: Used with Interfaces and Classes. A Class implements a interface.

class Employee implements IPerson

readonly: A keyword that can only be used in a class.

let readonly _secretCode: string = "abc";

super: Each derived class that contains a constructor function must call super() which will execute the constructor of the base class.

class WebDeveloper extends Developer
{
    favoriteEditor: string;

    constructor(editor: string)
    {
super();
        this.favoriteEditor = editor;
    }
}

Each derived class that contains a constructor function must call super() which will execute the constructor of the base class . What’s more, before we ever access a property on this in a constructor body, we have to call super(). This is an important rule that TypeScript will enforce.