👷 Enable terser ecma: 2015 and module: true options

[sethfowler-datadog]

Motivation

This is one of a series of PRs experimenting with enabling more aggressive options for Terser, with the goal of reducing the size of the browser SDK bundles.

Changes

This PR enables the following options:

• ecma: 2015
• module: true

Testing

• Local
• Staging
• Unit
• End to end

---

I have gone over the contributing documentation.

[cit-pr-commenter]

Bundles Sizes Evolution

📦 Bundle Name	Base Size	Local Size	𝚫	𝚫%	Status
Rum	148.94 KiB	148.91 KiB	-26 B	-0.02%	✅
Logs	52.26 KiB	52.25 KiB	-13 B	-0.02%	✅
Rum Slim	107.40 KiB	107.39 KiB	-13 B	-0.01%	✅
Worker	24.50 KiB	24.49 KiB	-13 B	-0.05%	✅

🚀 CPU Performance

Action Name	Base Average Cpu Time (ms)	Local Average Cpu Time (ms)	𝚫
addglobalcontext	0.003	0.008	0.005
addaction	0.049	0.299	0.250
addtiming	0.002	0.006	0.004
adderror	0.074	0.190	0.117
startstopsessionreplayrecording	0.010	0.045	0.036
startview	0.665	2.185	1.520
logmessage	0.037	0.191	0.155

🧠 Memory Performance

Action Name	Base Consumption Memory (bytes)	Local Consumption Memory (bytes)	𝚫 (bytes)
addglobalcontext	26.46 KiB	29.63 KiB	3.17 KiB
addaction	54.94 KiB	55.43 KiB	492 B
addtiming	26.67 KiB	27.24 KiB	583 B
adderror	60.15 KiB	61.65 KiB	1.50 KiB
startstopsessionreplayrecording	25.44 KiB	27.19 KiB	1.75 KiB
startview	425.10 KiB	426.12 KiB	1.01 KiB
logmessage	55.77 KiB	56.32 KiB	560 B

🔗 RealWorld

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.69%. Comparing base (edd35a5) to head (c343aef).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3413      +/-   ##
==========================================
- Coverage   92.71%   92.69%   -0.03%     
==========================================
  Files         301      301              
  Lines        7896     7896              
  Branches     1806     1806              
==========================================
- Hits         7321     7319       -2     
- Misses        575      577       +2     

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