Recently, I started playing around with the TypeScript library. In case you’re not familiar: the language is a superset of JavaScript that adds optional typing. It’s very similar to . But that’s not important here. TypeScript Flow What’s interesting is that the TypeScript is a JavaScript library that includes a parser (text → AST) and printer (AST → text). It’s able to parse not only TypeScript, but also plain JavaScript as well as JSX and even Flow. What’s an AST? library Let me show you a simple example: <a href="https://medium.com/media/cfec2fceee90a134012ec5ea19d295a5/href">https://medium.com/media/cfec2fceee90a134012ec5ea19d295a5/href</a> Now, the interesting part is that you can change the Abstract Syntax Tree and reprint the code. For example: <a href="https://medium.com/media/948b5fa76ca557fdce80e259ac517b4d/href">https://medium.com/media/948b5fa76ca557fdce80e259ac517b4d/href</a> Or you can have fun and push it a level further, by parsing the script’s own code and asking it to rewrite itself. I’m not sure why you’d do that, but hey, why not? <a href="https://medium.com/media/093b4502a225024bd41ea225a9024c9d/href">https://medium.com/media/093b4502a225024bd41ea225a9024c9d/href</a> Clone if you’d like to try it. this GitHub repo That’s it for today. If you liked this post, you may also like my previous post about . parsing your own language with ANTLR4 Thanks for reading, have a nice day!

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Parsing JavaScript in JavaScript

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