What is TypeScript?

TypeScript is a strongly typed programming language that builds on JavaScript, giving you better tooling at any scale. Writing secure and maintainable JavaScript codebase is very hard, TypeScript is created to helps developer to write secure and maintainable JavaScript codebase.

Here is example of TypeScript code:

type Result = "pass" | "fail";

function verify(result: Result) {
    if (result === "pass") {
        console.log("Passed");
    } else {
        console.log("Failed");
    }
}

If you pass any string other than "pass" and "fail" to the verify function, the code above won’t compile.

If you are JavaScript developer, it’s recommended to write the codebase in TypeScript instead of JavaScript. You can write one codebase and target multiple JavaScript standards like ECMAScript and CommonJS. So you don’t need to worry about specific JavaScript standard.

You can also write one program that can run on the server and browser using TypeScript. If you don’t use TypeScript you need to write multple JavaScript code that conform with different JavaScript standard.

If you want to learn more about TypeScript, go to the TypeScript Handbook.