TypeScript is an open source programming language developed by Microsoft and first released in 2012. It is designed to add type safety to JavaScript while conforming as closely as possible to the syntax and semantics of the ECMAScript standard.
It is a syntactical superset of the JavaScript programming language; all valid JavaScript source code is also valid TypeScript source code, but not vice-versa. TypeScript compiles (or transpiles) to JavaScript, meaning that it can be utilized to target any JavaScript environment. It can be used to develop JavaScript for both client-side and server-side applications.