Bit of personal history, skip with pleasure

I remember my time when I used to write php codes, everytime I needed to debug I would echo whatever variable was there. Debugging has been quite easy since i have switched to rails, just simple binding.pry in a code and server stops there and let's me debug my code.

Previously, probably influenced by my past habit with php of printing everything to screen with echo, I would use console.log(); in js to print variables and see if anything went wrong. I would sometimes wish if there was something like binding.pry. Then I realised js has debugger that works just like binding.pry.

Debugger

The debugger statement is used to tell the JavaScript engine to open a debugger if one is available and treat the statement as a breakpoint. ES5 12.15

As mentioned above, your code will stop at debugger if your console is open in browser. Then you can use console for debugging purposes. But can you guess what will happen if you push your code containing debugger? It is probably the worst way you can show your carelessness.

Jshint to the rescue shows Unexpected 'debugger'. It is regarded as best practice to remove all console.log(); and debugger; from the code before sending pull request to ensure they never reach production environment.