Ngoài TypeScript thì còn có các altJS khác như PureScript

TypeScript làm cho JS giống C#, PureScript làm nó giống Haskell

altJS compile-to-JavaScript language list

List of languages that compile to JS · jashkenas/coffeescript Wiki · GitHub

To fully answer “Why learn PureScript?” we must answer three other questions:

• Why one should use Javascript to build programs…
• …but not write Javascript to build it…
• …and write Purescript instead of alternatives

Nguồn:: Why Learn PureScript - PureScript: Jordan’s Reference

Intro to PureScript for TypeScript developers - Advanced Web Machinery

Developers didn’t want to use a new language, they wanted to use an existing language. When TS arrived, people were trying to build Node and Browser software with JavaScript, which meant there was a lot of existing codebases out there, and re-writing them all to be Dart was infeasible. TS won out because it is a superset of JavaScript, which means all those existing codebases could be enhanced by TypeScript, it was very low impact.