Last week whilst investigating a production issue I discovered the following two priceless debugging techniques on chrome dev tools. These eventually helped me solve the bug so I'm sharing them here now. Hopefully these will be useful to others.
You can console log without changing the source code! This means you can even console log production code or any code for that matter accessible via dev tools:
'Input value is:', input.
You can add a condition to a breakpoint so the debugger only kicks in when the condition is met. This saves you from having to repeatedly click the resume button only to miss the actual problematic case because of the mad clicking:
Hope that helps. Till next time!