Typescript without Typescript

If I want types in JavaScript, I have to use TypeScript. Or do I? Recently, several open-source projects (e.g., Svelte Kit) have ditched TypeScript but kept types. And the community collectively said, "Wait, what?!" Because they suddenly discovered that JsDoc exists.

So you don’t get lost in all this, I’ll tell you what JsDoc is, how to use it, what it lacks compared to TypeScript, and conversely, what it offers that TypeScript doesn’t. Don’t worry, I’m not going to try to convince you to switch to JsDoc. But I want you to know about this option and keep it in your back pocket for when it really comes in handy.