I'm testing several webapps on Firefox 58 and the problem is that when I insert the debugger statement on my javascript code(react 16+) and the app hot reloads itself, the first time the debugger tab of the developer tools shows all the info I need and the current state of my app. But, If I modify something else and reload my app or just refresh the current page, with the debugger statement still on the code, the browser slows down until the UI of the entire browser is unresponsive to my mouse clicks and the debugger tab shows nothing at all. The only way to be able to exit this state is to close the developer tools, where the browser exits its frozen status and all the tabs and the UI start to function again. This was happening in firefox 57, also I've tested the same code on Chrome and none of the freezing occurs.