TypeScript has two birthdays – by 2012, it had already been under development for two years internally at Microsoft.
"A type system is one way you can reason about your code. It's the ability to check your code before you run and deploy it. Without types in a language, that's almost impossible," Hejlsberg explains.
Rosenwasser said there have been requests for TypeScript to be a "a linter, a bundler, an optimizer/minifier, a build orchestrator, a bundler (again), and more." But he also said Microsoft doesn't want to disrupt the ecosystem too much by displacing them.