[reactive-element] Assume native constructible stylesheet support #5120

justinfagnani · 2025-10-13T17:39:47Z

DO NOT MERGE

Exploration of how much code we could remove if we assumed constructible stylesheet support, which is Baseline and available cross-browser since March 2023: https://developer.mozilla.org/en-US/docs/Web/API/CSSStyleSheet/CSSStyleSheet

This change saves 650 bytes.

changeset-bot · 2025-10-13T17:39:50Z

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Latest commit: 4f6e612

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github-actions · 2025-10-13T17:39:59Z

📊 Tachometer Benchmark Results

Summary

nop-update

this-change, tip-of-tree, previous-release: unsure 🔍 -6% - +9% (-0.74ms - +1.10ms)
^{this-change vs tip-of-tree}

render

this-change: 44.66ms - 58.05ms
this-change, tip-of-tree, previous-release: unsure 🔍 -5% - +5% (-0.92ms - +0.99ms)
^{this-change vs tip-of-tree}
this-change, tip-of-tree, previous-release: unsure 🔍 -2% - +2% (-0.65ms - +0.74ms)
^{this-change vs tip-of-tree}
this-change, tip-of-tree, previous-release: unsure 🔍 -6% - +57% (-1.45ms - +24.20ms)
^{this-change vs tip-of-tree}

update

this-change: 471.18ms - 478.40ms
this-change, tip-of-tree, previous-release: unsure 🔍 -4% - +5% (-1.67ms - +1.80ms)
^{this-change vs tip-of-tree}
this-change, tip-of-tree, previous-release: unsure 🔍 -1% - +2% (-0.91ms - +1.55ms)
^{this-change vs tip-of-tree}
this-change, tip-of-tree, previous-release: unsure 🔍 -3% - +1% (-12.71ms - +3.89ms)
^{this-change vs tip-of-tree}

update-reflect

this-change: 457.06ms - 461.63ms
this-change, tip-of-tree, previous-release: unsure 🔍 -2% - +1% (-9.62ms - +7.13ms)
^{this-change vs tip-of-tree}

Results

this-change

Browser: chrome-headless 140.0.0.0
Sample size: 50
Built by: Benchmarks #7005
Commit: 4f6e612

render

Version	Avg time	vs
	44.66ms - 58.05ms	-

update

Version	Avg time	vs
	471.18ms - 478.40ms	-

update-reflect

Version	Avg time	vs
	457.06ms - 461.63ms	-

this-change, tip-of-tree, previous-release

Browser: chrome-headless 140.0.0.0
Sample size: 30
Built by: Benchmarks #7005
Commit: 4f6e612

render

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	19.39ms - 20.88ms	-	unsure 🔍 -5% - +5% -0.92ms - +0.99ms	unsure 🔍 -2% - +8% -0.36ms - +1.46ms
tip-of-tree tip-of-tree	19.50ms - 20.70ms	unsure 🔍 -5% - +5% -0.99ms - +0.92ms	-	unsure 🔍 -1% - +7% -0.28ms - +1.31ms
previous-release previous-release	19.06ms - 20.11ms	unsure 🔍 -7% - +2% -1.46ms - +0.36ms	unsure 🔍 -6% - +1% -1.31ms - +0.28ms	-

update

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	35.98ms - 38.40ms	-	unsure 🔍 -4% - +5% -1.67ms - +1.80ms	unsure 🔍 -5% - +3% -2.03ms - +1.16ms
tip-of-tree tip-of-tree	35.88ms - 38.36ms	unsure 🔍 -5% - +4% -1.80ms - +1.67ms	-	unsure 🔍 -6% - +3% -2.12ms - +1.11ms
previous-release previous-release	36.59ms - 38.66ms	unsure 🔍 -3% - +5% -1.16ms - +2.03ms	unsure 🔍 -3% - +6% -1.11ms - +2.12ms	-

nop-update

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	12.29ms - 13.61ms	-	unsure 🔍 -6% - +9% -0.74ms - +1.10ms	unsure 🔍 -0% - +15% -0.01ms - +1.76ms
tip-of-tree tip-of-tree	12.13ms - 13.41ms	unsure 🔍 -8% - +6% -1.10ms - +0.74ms	-	unsure 🔍 -2% - +13% -0.17ms - +1.56ms
previous-release previous-release	11.49ms - 12.66ms	unsure 🔍 -13% - -0% -1.76ms - +0.01ms	unsure 🔍 -12% - +1% -1.56ms - +0.17ms	-

this-change, tip-of-tree, previous-release

Browser: chrome-headless 140.0.0.0
Sample size: 50
Built by: Benchmarks #7005
Commit: 4f6e612

render

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	34.70ms - 35.71ms	-	unsure 🔍 -2% - +2% -0.65ms - +0.74ms	unsure 🔍 -3% - +1% -1.02ms - +0.39ms
tip-of-tree tip-of-tree	34.68ms - 35.64ms	unsure 🔍 -2% - +2% -0.74ms - +0.65ms	-	unsure 🔍 -3% - +1% -1.04ms - +0.33ms
previous-release previous-release	35.03ms - 36.00ms	unsure 🔍 -1% - +3% -0.39ms - +1.02ms	unsure 🔍 -1% - +3% -0.33ms - +1.04ms	-

update

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	71.64ms - 73.40ms	-	unsure 🔍 -1% - +2% -0.91ms - +1.55ms	unsure 🔍 -2% - +2% -1.35ms - +1.09ms
tip-of-tree tip-of-tree	71.35ms - 73.06ms	unsure 🔍 -2% - +1% -1.55ms - +0.91ms	-	unsure 🔍 -2% - +1% -1.65ms - +0.75ms
previous-release previous-release	71.81ms - 73.50ms	unsure 🔍 -2% - +2% -1.09ms - +1.35ms	unsure 🔍 -1% - +2% -0.75ms - +1.65ms	-

this-change, tip-of-tree, previous-release

Browser: chrome-headless 140.0.0.0
Sample size: 50
Built by: Benchmarks #7005
Commit: 4f6e612

render

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	46.47ms - 66.02ms	-	unsure 🔍 -6% - +57% -1.45ms - +24.20ms	unsure 🔍 -19% - +36% -9.30ms - +17.92ms
tip-of-tree tip-of-tree	36.56ms - 53.17ms	unsure 🔍 -40% - +0% -24.20ms - +1.45ms	-	unsure 🔍 -36% - +9% -19.66ms - +5.53ms
previous-release previous-release	42.46ms - 61.40ms	unsure 🔍 -31% - +16% -17.92ms - +9.30ms	unsure 🔍 -14% - +46% -5.53ms - +19.66ms	-

update

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	482.75ms - 495.34ms	-	unsure 🔍 -3% - +1% -12.71ms - +3.89ms	unsure 🔍 -3% - +1% -13.13ms - +3.86ms
tip-of-tree tip-of-tree	488.05ms - 498.87ms	unsure 🔍 -1% - +3% -3.89ms - +12.71ms	-	unsure 🔍 -2% - +2% -8.09ms - +7.64ms
previous-release previous-release	487.98ms - 499.39ms	unsure 🔍 -1% - +3% -3.86ms - +13.13ms	unsure 🔍 -2% - +2% -7.64ms - +8.09ms	-

update-reflect

Version	Avg time	vs this-change	vs tip-of-tree tip-of-tree	vs previous-release previous-release
this-change	488.43ms - 499.40ms	-	unsure 🔍 -2% - +1% -9.62ms - +7.13ms	unsure 🔍 -2% - +1% -8.51ms - +7.09ms
tip-of-tree tip-of-tree	488.84ms - 501.49ms	unsure 🔍 -1% - +2% -7.13ms - +9.62ms	-	unsure 🔍 -2% - +2% -7.87ms - +8.94ms
previous-release previous-release	489.09ms - 500.17ms	unsure 🔍 -1% - +2% -7.09ms - +8.51ms	unsure 🔍 -2% - +2% -8.94ms - +7.87ms	-

_{tachometer-reporter-action v2 for Benchmarks}

github-actions · 2025-10-13T17:41:26Z

The size of lit-html.js and lit-core.min.js are as expected.

[reactive-element] Assume native constructible stylesheet support

4f6e612

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[reactive-element] Assume native constructible stylesheet support #5120

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📊 Tachometer Benchmark Results

Summary

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render

update

update-reflect

Results

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update

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render

update

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📊 Tachometer Benchmark Results

Summary

nop-update

render

update

update-reflect

Results

render

update

update-reflect

render

update

nop-update

render

update

render

update

update-reflect

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