I didn't understand some of the mentioned benefits of PHP. Progressively adding types: This isn't PHP it's hack. How is this different than typescript or flow

I didn't understand some of the mentioned benefits of PHP. Progressively adding types: This isn't PHP it's hack. How is this different than typescript or flow? Edit/refresh vs edit/restart server. It seems like it's been several years that there have been things like meteor or webpack that make iteration super fast on JavaScript. Is that iteration slower than PHP?