Go to Firebase SDK Plugin Properties
2. Enable Debug
It is recommended to turn this feature off when exporting for the final/public release of your app.
The JavaScript Console is located in the Developer Tools of your browser.
During preview, click on your Preview window, and then simply Press F12 and Go to the "Console" Tab.
Simply add Eruda Console Plugin to your Project to start Debugging. Disable Worker Mode for this to work. (Go to Project Properties > Advanced > "Use Worker": "No")
Plugin Link: https://www.construct.net/en/make-games/addons/551/eruda-console-no-worker
(This plugin also works on Android and iOS)