Features of TypeScript

Here are some intresting features of TypeScript:

1. Instant Feedback 

• JavaScript is a dynamic language where we can do all kinds of crazy things like reference variables that don't exist or work with objects of unknown shape.

• The code is interpreted by the browser and we won't catch this error until runtime when the browser throws an error.

• Typescript prevents this from ever happening by extending js with types by providing instant feedback.

2. Superset of JavaScript 

• The language is a strict superset of Javascript which means when you open a Typescript file you can write plain Javascript with all of its extra features being completely optional.

3. Compiled Language 

• The reason we get this instant feedback is that Typescript behaves like a compiled language while Javascript is the compilation target.
• We can run the Typescript compiler using the 'tsc' command.

• When compiled it'll take the Transcript file and transpile it into Javascript.

4. Customize Compiler Behavior

Typescript project will have a ts config file that provides an infinite number of ways to customize the behavior of the compiler.

5. Static Typing 

• The primary goal of Typescript is to enable static typing. One way it achieves that is by letting us annotate our code with types.

let appName: string;    //we can take variable followed by annotation and specifying its type thats known as explicit type
appName=23; //Error
appName='jacob'  //Correct

• If we try to initialize the variable with the wrong value we get an error.
• Alternatively, if we set an initial value it'll implicitly infer the type.

let appName= 'jacob'; //automatically takes up the type.

• If we want to change the type after we can just annotate with the 'any' type.

let appName: any = 'jacob';  

appName=20;  //This way we can opt out of type anytime.