👷‍♀️ [RUM-6424] Change webpack chunk config to speed up local unit tests

[cy-moi]

Motivation

Running unit tests locally is slow because we build dependency bundles with every change. We should speed it up to improve the development experience.

Webpack automatically split chunks so not all chunks will be rebuilt. Currently we set it to false due to dependency issues between our bundles. But we don't need to rebuild everything all the time.

Changes

Add a 'scope' command to avoid rebuilding all bundles when running scoped unit tests.

Testing

• Local
• Staging
• Unit
• End to end

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I have gone over the contributing documentation.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.66%. Comparing base (d2c974e) to head (80960df).
Report is 30 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3057      +/-   ##
==========================================
- Coverage   93.67%   93.66%   -0.02%     
==========================================
  Files         275      275              
  Lines        7610     7610              
  Branches     1707     1707              
==========================================
- Hits         7129     7128       -1     
- Misses        481      482       +1     

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[cit-pr-commenter]

Bundles Sizes Evolution

📦 Bundle Name	Base Size	Local Size	𝚫	𝚫%	Status
Rum	160.95 KiB	160.95 KiB	0 B	0.00%	✅
Logs	56.00 KiB	56.00 KiB	0 B	0.00%	✅
Rum Slim	109.53 KiB	109.53 KiB	0 B	0.00%	✅
Worker	25.21 KiB	25.21 KiB	0 B	0.00%	✅

🚀 CPU Performance

Action Name	Base Average Cpu Time (ms)	Local Average Cpu Time (ms)	𝚫
addglobalcontext	0.001	0.001	-0.000
addaction	0.030	0.031	0.001
addtiming	0.001	0.001	-0.000
adderror	0.032	0.032	0.000
startstopsessionreplayrecording	0.888	0.865	-0.023
startview	0.970	0.973	0.003
logmessage	0.020	0.019	-0.001

🧠 Memory Performance

Action Name	Base Consumption Memory (bytes)	Local Consumption Memory (bytes)	𝚫 (bytes)
addglobalcontext	7.29 KiB	9.67 KiB	2.38 KiB
addaction	39.11 KiB	39.01 KiB	-100 B
addtiming	5.96 KiB	8.00 KiB	2.03 KiB
adderror	43.72 KiB	46.14 KiB	2.42 KiB
startstopsessionreplayrecording	4.29 KiB	5.50 KiB	1.21 KiB
startview	460.56 KiB	467.42 KiB	6.86 KiB
logmessage	39.25 KiB	40.27 KiB	1.02 KiB

🔗 RealWorld

[amortemousque]

Why are we only doing it for local unit tests?

[cy-moi]

I don't think we run multiple times consecutively for cicd with watch option. This only speeds it up when we want to watch changes. BrowserStack unit tests would fail without splitChunk:false.

[cy-moi]

Same as the developer-extension, rum-react is also failed to be excluded and we cannot make it compatible with IE. So let's merge this in v6 directly.