> typesafety was the main benefit of JSX
Do you have a source for that?
Do you have a source for that?
Before JSX came out, there were tons of templating systems that let you embed HTMLish things in JS: Handlebars, Mustache, EJS, Pug, Angular templates.
JSX’s big innovation was taking the way XHP promoted HTML to first class syntax and applying it to JS. The big difference between that and the template systems that came before it is JSX is statically analyzable (by your type checker, or by other tools), which means you can scale it to FB scale.
You're right that when it came out it's main innovation was separation of concerns and composability, but types or static analysis were not part of the value proposition at the time.
On the other hand, both TypeScript and Flow support type checking for JSX attributes (and child elements to some extent)