[fix] Fix broken playground

[nmn]

What changed / motivation ?

The playground compilation is currently broken. This fixes that.

[vercel]

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1 Skipped Deployment

Project	Deployment	Actions	Updated
stylex	Ignored		Sep 5, 2026 12:02am UTC

[Copilot]

🟡 Changes recommended

The newly added test mutates globalThis.global but doesn’t verify the mutation succeeded, so it may not actually validate the intended “no global alias” scenario.

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Pull request overview

Fixes StyleX’s static evaluator to work in the playground/browser bundle by avoiding Node-specific global usage and instead using globalThis.

Changes:

• Introduce a globalObject alias to globalThis for runtime-global access in both Node and browser bundles.
• Replace global.* lookups in the evaluator with globalObject.*.
• Add a regression test intended to validate evaluation when the Node global alias is absent.

File summaries

File	Description
packages/@stylexjs/babel-plugin/src/utils/evaluate-path.js	Switch evaluator’s global access from Node global to globalThis via globalObject to support browser bundles.
packages/@stylexjs/babel-plugin/src/utils/tests/evaluate-path-test.js	Add coverage for evaluating built-ins in an environment without the Node global alias.

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 1
• Review effort level: Lite

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[github-actions]

workflow: benchmarks/perf

Comparison of performance test results, measured in operations per second. Larger is better.
yarn workspace v1.22.22
yarn run v1.22.22
$ node ./compare.js /tmp/tmp.pvLH4CrTEV /tmp/tmp.wK7A8BGzY5

Results	Base	Patch	Ratio
babel-plugin: stylex.create
· basic create	584	586	1.00	+
· complex create	64	66	1.03	+
babel-plugin: stylex.createTheme
· basic themes	450	462	1.03	+
· complex themes	32	32	1.00
Done in 0.08s.
Done in 0.34s.

[github-actions]

workflow: benchmarks/size

Comparison of minified (terser) and compressed (brotli) size results, measured in bytes. Smaller is better.
yarn workspace v1.22.22
yarn run v1.22.22
$ node ./compare.js /tmp/tmp.6Ud5kLYgDR /tmp/tmp.YbX4NRdkPv

Results	Base	Patch	Ratio
@stylexjs/stylex/lib/cjs/stylex.js
· compressed	1,535	1,535	1.00
· minified	5,166	5,166	1.00
@stylexjs/stylex/lib/cjs/inject.js
· compressed	1,793	1,793	1.00
· minified	4,915	4,915	1.00
benchmarks/size/.build/bundle.js
· compressed	496,650	496,650	1.00
· minified	4,847,840	4,847,840	1.00
benchmarks/size/.build/stylex.css
· compressed	99,735	99,757	1.00	+
· minified	740,755	748,850	1.01	+
Done in 0.09s.
Done in 0.34s.