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April 14th, 2021 × #Chrome#Firefox#DevTools#Debugging

Dev Tools Tabs Explained — Plus Tips & Tricks

Scott and Wes bos explain the dev tools tabs in Chrome and Firefox, detailing what each one does and providing tips and tricks for using them effectively.

Wes Bos

Wes Bos Host

Scott Tolinski

Scott Tolinski Host

or
Show Notes Transcript

In this episode of Syntax, Scott and Wes talk about dev tools tabs, what each tab does and how you can use them.

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Show Notes

3:50 - Network

  • See all requests, filter by type or name
  • Used to understand all requests coming or going
  • Turn off caching
  • View timing
  • See the true GZIP size
  • Slow down network speed
  • See time for page load
  • Copy as fetch or CURL
  • View request, response, and headers
  • See CORS issues
  • See which requests have happened
  • See if an asset is cached (both in dev tools, also Cloudflare)
  • See blocked requests because of extensions
  • Tip: You can see the network info from the console in Firefox

22:03 - Memory

  • See what is taking up memory
    • Strings
    • DOM nodes
    • Objects
    • Actual .js

26:44 - Performance

  • Click record and use the site
  • Flame chart useful for finding slow functions and debugging janky animations
  • Get FPS in coordination with flame chart
  • Save performance recording data to be able to share for debugging
  • You can also upload saved data to debug without using the site

30:48 - Console

  • Interfaces with the JS runtime
  • Shows errors, warnings, and logs
  • Tip: Negate noisy warnings/errors that clutter your console with -
  • Tip: Use $0 to select current element
    • $1 for second last
    • $r for current React element
  • Tip: Use $$ to shortcut Query SelectorAll and Array.from
  • Tip: Use $ to shortcut Query Selector

40:28 - Storage / Application

  • Working with LocalStorage, Cookies, Index DB, and Session Storage

44:56 - Audit / Lighthouse (Chrome and Firefox)

  • Run lighthouse to check for performance, accessibility, and UI stuff
  • Not the silver bullet audit that many people think it is
    • Colors are sometimes like "Really?!"
  • Can be helpful regardless

50:28 - DOM Tab

  • Firefox only
  • Shows everything that is in the scope of the browser

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