Introduction to TypeScript
TypeScript is an open source language that builds on JavaScript, meaning all valid JavaScript code is also TypeScript code. It allows us to write types of objects, variables, or functions, providing better documentation and allowing TypeScript to validate the fact that our code is working as expected, but writing types is purely optional since TypeScript has type inference and, most of the time, TypeScript will know which type a constant is by its value.
When we're using plain JavaScript and we're developing a website with a lot of variables, sometimes, we try to access methods of our variables that don't exist.
For instance, when accessing .toLowerCase() of a number variable:
const value = 10_000 console.log(value.toLowerCase())
This code in our development editor won't log an error, or we won't see any change in our code. But let's say we try to run this code:
> value.toLowerCase() Uncaught TypeError: value...
