My (unpopular?) take is that JavaScript should suffice.

Once I feel the need for TypeScript, I've done something wrong. For example, built my whole frontend with JavaScript or built my backend in JavaScript.

JavaScript's use case for me is sprinkling it where needed in browser. Anything extra and it feels wrong tool for the job.

Frankly, I believe whole existence of TypeScript is a mistake – we should've never used JavaScript at a scale where static typing becomes necessary.

Having said all that, I'd love to be able to write gradually typed JavaScript (i.e. TypeScript) in the browser. Gradual typing is still greatly beneficial, even in my sprinkles.