It's basically equivalent to Scala for the compilation itself (no noticeable difference). But the browser refresh in dev mode can take up to 5 seconds (or down

It's basically equivalent to Scala for the compilation itself (no noticeable difference). But the browser refresh in dev mode can take up to 5 seconds (or down to under 1 sec, depends on the machine). There is a tool that helps with this by using clever tricks to refresh the browser without reparsing the standard lib: https://github.com/lihaoyi/scala-js-workbench https://github.com/lihaoyi/scala-js-workbench