TypeScript fundamentals

According to its website, https://www.typescriptlang.org/, TypeScript is a typed superset of JavaScript that compiles to plain JavaScript, any browser, any host, any OS--open source. TypeScript is a typed superset of ES6 JavaScript. It can be noted that ES6 JavaScript is a superset of ES5 JavaScript that runs native in all modern browsers. 

You can get the set up and start programming in TypeScript using the following command:

npm install -g typescript

The following are some salient features of the TypeScript:

• Typed language: It is a typed language. The following data types are supported--number, string, array, list, null, and enum. The user object is represented by the following code:

        let firstName: string = "Calvin";
        let age: number = 19;
        let gender: string = "male";
        let isEnrolled: boolean = false;
        let address: [string, string, string] = 
            ["Nizampet Road, Kukatpally", "Hyderabad", "India"];

• Variable declarations: It...