Finding faults in running code.
WHAT THE DEBUGGER PROVIDES
Pausing at a chosen line Inspecting every value in scope Stepping through execution Examining the call stack Watching expressions
WHY IT BEATS LOGGING VALUES
It shows everything without modifying code, and lets you explore.
WHAT TO LEARN
Setting breakpoints, including conditional ones Breaking on exceptions Breaking when an element changes Stepping into, over and out of calls
WHAT CONDITIONAL BREAKPOINTS SOLVE
Pausing only when a condition holds, inside a loop running thousands of times.
WHAT BREAKING ON ELEMENT CHANGES SOLVES
Finding what modified something, when you do not know where.
WHAT SOURCE MAPS PROVIDE
Debugging your original code rather than the minified output.
WHY THAT MATTERS
Minified code is unreadable, and a stack trace against it is useless.
WHAT TO CONFIGURE
Source map generation in your build.
WHAT TO CHECK WHEN A BREAKPOINT DOES NOT HIT
Whether the code actually runs Whether source maps are correct Whether the file is the one being executed
WHAT TO DO WITH ASYNCHRONOUS CODE
Use the asynchronous stack, which shows what initiated the operation.
