Is there a more simple JS linter that does 90% of what basic TypeScript does? I mostly use simple types (basic times, Promises, arrays, and a bunch of interfaces) and I find TypeScript valuable for that. It saved me a few times from accidentally treating a Promise<Whatever> as Whatever for example – and other things.

But I heard an interesting argument: It's not TypeScript vs. vanilla JS; it is TypeScript vs. whatever else full-blown linting/IDE comfort you can get by still writing vanilla JS with no transpile step.