Inspect network responses and CORS issues

Scott and Wes detail the tips and tools you need to get better at debugging.

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Show Notes

4:00

• Read the stack trace

7:35

• Make sure you aren’t debugging production
• Make sure you’re not cached

8:40

• Check the network panel for the whole response
• CORS (Cross-Origin Resource Sharing)

12:04

• Use debugger commands in the browser
• Set breakpoints (race conditions

13:40

• Use Source Maps

15:29

• Make full use of all console methods
  • console.group/groupEnd/info/
  • console.log({objNAme})

17:02

• View your code in other browers
• Make sure your browser is up to date

18:50

• Step into and step over function
• Useful for especially tricky issues

19:47

• Look into Scope in dev tools panel

20:33

• Recreate it in CodePen or Create React App
  • Helps to quarantine your code
  • Verify where the problem actually is

24:12

• Take a break
  • Helps clear your head and approach your problem from a different angle

25:40

• Rubber Duck Debugging
  • Forcing yourself to talk it out will often reveal problems/issues

26:40

• Check Github issues / ask in Slack
  • Leave your solution in the comments for others

28:12

• Use Node --inspect flag

29:57

• Read the code in your libs (if you can)

32:34 - Chrome Dev Tools Tabs Rundown

• 33:10 - Network tab
• 34:15 - Preformance tab
• 35:58 - Lesser known tools
  • 36:15 - Firefox Grid Debug
  • 36:20 - Firefox Fonts tab
  • 37:10 - More tools (three dots menu in top right of Chrome Dev Tools window)
  • 37:39 - Chrome Animations Inspector
  • 38:34 - /dev tips & Modern DevTools Course
  • 39:41 - Chrome & FF Layers for 3d and full view of canvas & window
  • 40:51 - Sensors for overriding fake devices sensors
    • Hot tip: Use Instagram on the desktop - Go to Instagram and set the user agent to iPad and it will work as it does on that actual device
    • Hot tip: Get free internet on a plane - If the airplane offers free internet for a certain device, change your user agent to that device and then switch back
  • 43:12 - Favorite DevTools extensions
    • Apollo
    • React
    • Redux
    • Vue
    • Lighthouse
    • JSON Formatter
• 44:06 - Application/Storage tab
• 44:41 - FireFox Grid Inspector

××× SIIIIICK ××× PIIIICKS ×××

• Scott: Hotel Tonight App
• Wes: Coffee table - If you’re trying to build an outdoor coffee table, use a peice of granite

Shameless Plugs

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