TypeScript
TypeScript is a strongly typed, object-oriented programming language that builds on JavaScript by adding static type definitions. It compiles to plain JavaScript and is designed for the development of large-scale applications, providing enhanced tooling and error checking at compile time. TypeScript is maintained by Microsoft and is widely used in modern web development, particularly with frameworks like Angular, React, and Vue.js.
Developers should learn TypeScript when working on large or complex JavaScript projects where type safety, better code maintainability, and improved developer experience are priorities. It is especially useful in enterprise applications, team environments to reduce bugs, and when using modern frameworks that have built-in TypeScript support. TypeScript's static typing helps catch errors early, provides better IDE support with autocompletion, and makes code more self-documenting.