Breaking: Tailwind CSS v4 support

[dcastil]

Closes #513
Closes #495

[github-actions]

Metrics report

At head commit 7f043a6 and base commit 47c87d8 at 2025-01-30T16:09:26.632Z

Size

Export	Size original	Size minified	Size minified and Brotli compressed
tailwind-merge esm	84.10 kB +16.1% 🔴	22.51 kB +10.7% 🔴	6.31 kB +9.8% 🔴
› createTailwindMerge	13.42 kB +6.3% 🔴	3.61 kB +6.3% 🔴	1.44 kB +4.8% 🔴
› extendTailwindMerge	83.39 kB +15.9% 🔴	21.88 kB +9.9% 🔴	6.04 kB +7.6% 🔴
› getDefaultConfig	67.63 kB +17.3% 🔴	17.38 kB +8.6% 🔴	4.49 kB +8.0% 🔴
› mergeConfigs	2.12 kB +46.4% 🔴	0.80 kB +77.9% 🔴	0.27 kB +15.5% 🔴
› twMerge	81.08 kB +15.3% 🔴	21.02 kB +8.3% 🔴	5.87 kB +8.0% 🔴
› validators	4.49 kB +49.4% 🔴	1.69 kB +33.8% 🔴	0.73 kB +14.8% 🔴
tailwind-merge cjs	84.36 kB +16.0% 🔴	28.36 kB +21.2% 🔴	6.63 kB +9.2% 🔴
tailwind-merge/es5 esm	89.36 kB +17.2% 🔴	24.44 kB +12.6% 🔴	6.52 kB +7.8% 🔴
› createTailwindMerge	15.27 kB +5.3% 🔴	4.20 kB +4.3% 🔴	1.56 kB +3.2% 🔴
› extendTailwindMerge	88.26 kB +16.8% 🔴	23.80 kB +11.8% 🔴	6.34 kB +8.3% 🔴
› getDefaultConfig	70.05 kB +19.1% 🔴	18.50 kB +11.7% 🔴	4.58 kB +9.5% 🔴
› mergeConfigs	2.46 kB +38.2% 🔴	0.87 kB +72.1% 🔴	0.29 kB +21.5% 🔴
› twMerge	85.35 kB +16.4% 🔴	22.74 kB +10.4% 🔴	6.10 kB +7.5% 🔴
› validators	6.09 kB +62.7% 🔴	2.23 kB +45.1% 🔴	0.76 kB +17.3% 🔴
tailwind-merge/es5 cjs	89.62 kB +17.1% 🔴	30.31 kB +22.2% 🔴	6.89 kB +9.8% 🔴

All size metrics

Export	Size original	Size minified	Size minified and Brotli compressed
tailwind-merge esm	84.10 kB +16.1% 🔴	22.51 kB +10.7% 🔴	6.31 kB +9.8% 🔴
› createTailwindMerge	13.42 kB +6.3% 🔴	3.61 kB +6.3% 🔴	1.44 kB +4.8% 🔴
› extendTailwindMerge	83.39 kB +15.9% 🔴	21.88 kB +9.9% 🔴	6.04 kB +7.6% 🔴
› fromTheme	0.16 kB 0%	0.08 kB 0%	0.09 kB 0%
› getDefaultConfig	67.63 kB +17.3% 🔴	17.38 kB +8.6% 🔴	4.49 kB +8.0% 🔴
› mergeConfigs	2.12 kB +46.4% 🔴	0.80 kB +77.9% 🔴	0.27 kB +15.5% 🔴
› twJoin	1.06 kB 0%	0.26 kB 0%	0.16 kB 0%
› twMerge	81.08 kB +15.3% 🔴	21.02 kB +8.3% 🔴	5.87 kB +8.0% 🔴
› validators	4.49 kB +49.4% 🔴	1.69 kB +33.8% 🔴	0.73 kB +14.8% 🔴
tailwind-merge cjs	84.36 kB +16.0% 🔴	28.36 kB +21.2% 🔴	6.63 kB +9.2% 🔴
tailwind-merge/es5 esm	89.36 kB +17.2% 🔴	24.44 kB +12.6% 🔴	6.52 kB +7.8% 🔴
› createTailwindMerge	15.27 kB +5.3% 🔴	4.20 kB +4.3% 🔴	1.56 kB +3.2% 🔴
› extendTailwindMerge	88.26 kB +16.8% 🔴	23.80 kB +11.8% 🔴	6.34 kB +8.3% 🔴
› fromTheme	0.21 kB 0%	0.10 kB 0%	0.09 kB 0%
› getDefaultConfig	70.05 kB +19.1% 🔴	18.50 kB +11.7% 🔴	4.58 kB +9.5% 🔴
› mergeConfigs	2.46 kB +38.2% 🔴	0.87 kB +72.1% 🔴	0.29 kB +21.5% 🔴
› twJoin	1.08 kB 0%	0.26 kB 0%	0.14 kB 0%
› twMerge	85.35 kB +16.4% 🔴	22.74 kB +10.4% 🔴	6.10 kB +7.5% 🔴
› validators	6.09 kB +62.7% 🔴	2.23 kB +45.1% 🔴	0.76 kB +17.3% 🔴
tailwind-merge/es5 cjs	89.62 kB +17.1% 🔴	30.31 kB +22.2% 🔴	6.89 kB +9.8% 🔴

[codspeed-hq]

CodSpeed Performance Report

Merging #518 will degrade performances by 12.27%

_{Comparing breaking-feature/513/tailwind-css-v4-support (7f043a6) with main (47c87d8)}

Summary

⚡ 1 improvements
❌ 1 (👁 1) regressions
✅ 3 untouched benchmarks

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
👁	collection without cache	187.8 ms	214.1 ms	-12.27%
⚡	init	6.4 ms	4.7 ms	+36.88%

[github-actions]

This was addressed in release v3.0.0.