⚡️ [RUM-6813] Lazy load session replay

[amortemousque]

Motivation

Use dynamic imports to lazy load Session Replay, reducing the bundle size by 3KB (compressed) for users without Session Replay. Transitioning from Webpack, which adds overhead via __webpack_require__, to a new bundler could save additional bytes.

Changes

• Configure ts module to ES2020
• Update test app to target node and ES2018 (fix ssr). I made to webpack config files:
  • webpack.ssr.js targeting node and used for the ssr test
  • webpack.web.js targeting web and used for e2e tests
• Lazy load startRecording using dynamic import
• Updated the deploy.js script to deploy chunks
• Updated the upload-source-maps.js script to upload chunks maps

Testing

• Local
• Staging
• Unit
• End to end

---

I have gone over the contributing documentation.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.64%. Comparing base (c185a3c) to head (2dde99c).
Report is 8 commits behind head on v6.

Additional details and impacted files

@@            Coverage Diff             @@
##               v6    #3152      +/-   ##
==========================================
+ Coverage   93.51%   93.64%   +0.13%     
==========================================
  Files         286      286              
  Lines        7552     7559       +7     
  Branches     1718     1718              
==========================================
+ Hits         7062     7079      +17     
+ Misses        490      480      -10     

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[amortemousque]

For now, I introduced an async version of runOnReadyState but if we agree on this lazy loading approach I'll refactor the original runOnReadyState to use promises.

[amortemousque]

Refactoring runOnReadyState is quite complexe. Let's keep asyncRunOnReadyState for now

[cit-pr-commenter]

Bundles Sizes Evolution

📦 Bundle Name	Base Size	Local Size	𝚫	𝚫%	Status
Rum	151.13 KiB	141.86 KiB	-9495 B	-6.14%	✅
Logs	50.67 KiB	50.67 KiB	0 B	0.00%	✅
Rum Slim	101.10 KiB	101.10 KiB	0 B	0.00%	✅
Worker	25.16 KiB	25.16 KiB	0 B	0.00%	✅

🚀 CPU Performance

Action Name	Base Average Cpu Time (ms)	Local Average Cpu Time (ms)	𝚫
addglobalcontext	0.002	0.002	0.000
addaction	0.034	0.038	0.004
addtiming	0.001	0.001	0.000
adderror	0.031	0.044	0.013
startstopsessionreplayrecording	0.764	0.008	-0.756
startview	0.920	0.341	-0.579
logmessage	0.022	0.018	-0.004

🧠 Memory Performance

Action Name	Base Consumption Memory (bytes)	Local Consumption Memory (bytes)	𝚫 (bytes)
addglobalcontext	8.38 KiB	9.73 KiB	1.35 KiB
addaction	41.34 KiB	41.98 KiB	651 B
addtiming	7.69 KiB	8.13 KiB	454 B
adderror	44.28 KiB	45.73 KiB	1.45 KiB
startstopsessionreplayrecording	5.85 KiB	6.09 KiB	249 B
startview	407.29 KiB	406.37 KiB	-943 B
logmessage	42.05 KiB	42.32 KiB	278 B

🔗 RealWorld

[thomas-lebeau]

💬 suggestion: ‏ You can set the suffix in gitlab when you start a manual job

[amortemousque]

Nice, good to know :)