JavaScript is a powerful and dynamic language. Due to the liberty of dynamic programming in JavaScript as per ES5 and earlier standards, it is our duty to structure and organize code. It will make the maintainability of code easier and also enable us to easily locate the code of a specific functionality we need. We can organize code by applying a modular pattern. Code can be separated into various modules, and the relevant code can be put in each module.

TypeScript made it easier to implement modular programming using the keyword module as per ECMAScript 6 specifications. Modules enable you to control the scope of variables, code reusability, and encapsulation. TypeScript supports two types of modules: internal and external.