Debugging

Created : July 12, 2020

Debugging is the process of finding and fixing errors within a script.

Debugging in Chrome

  • Open developer tools (command + option + I)
  • Select Sources panel
  • How to pause the code to debug

    • Breakpoint : a point of code where the debugger will automatically pause the JavaScript execution.

      • While the code is paused, we can examine current variables, execute commands in the console etc. = we can debug it
    • Insert debugger; inside code

      • code editor안에서 breakpoint 설정할때 편함
    • breakpoints 설정한후 페이지를 reload(command + R)하면 자동으로 debugger가 실행됨
  • Paused on breakpoint

    • Call Stack : shows the nested calls chain.
    • Scope : current variables. (local / global)
  • Tracing the execution

    • Resume : continue the execution
    • Step : run the next command (모든 statement들을 하나하나씩 실행함)
    • Step over : run the next command, but don’t go into a function.
    • Step into : go into async code, waiting for them if necessary.
    • Step out : continue the execution and stop it at the very last line of the current function.
    • Pause on exceptions (automatic pause in case of an error) : When enabled, a script error automatically pauses the execution.