JavaScript has many peculiarities mostly caused through dynamic typing and in the past I found it a pain in the a**e especially when it came to debugging. TypeScript was my saviour and I use it for large projects such as canvasGUI. For small sketches and demos I am happy to use p5.js and JavaScript with Processing’s web editor.
I think being able to use TypeScript in the web-editor would provide a great route for programmers to learn TypeScript.