From JavaScript to TypeScript
Invented in 1995, JavaScript was designed as a small scripting language for simple web pages in browsers. It wasn’t until 1999 that JavaScript was capable of supporting the kinds of dynamic web pages we see today, and using JavaScript that way wasn’t common practice until 2005.
To serve its original use-case, JavaScript was designed to be very flexible and easy to use for small applications. These features make JavaScript a great first language to learn, but they also make it less-than-ideal for building larger-scale applications with hundreds or even thousands of files. Stricter programming languages will inform the developer when they change one area of code in a way that will break other areas. JavaScript will not, which often leads to unexpected behavior at runtime.
To address these shortcomings, Microsoft developed TypeScript and released publicly in 2012 to blend the flexibility of JavaScript with the advantages of a stricter language.
TypeScript is a programming language that adds types to JavaScript. It allows us to write JavaScript with a set of tools called a type system that can spot potential bugs in, clarify the structure of, and help refactor our code. In addition, TypeScript added newer JavaScript language features, such as arrow functions and classes, years before they were added to JavaScript officially.