Add benchmarks and integrate CodSpeed

.github/workflows/test.yml

@@ -37,3 +37,20 @@ jobs:
         uses: codecov/codecov-action@v4.0.1
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
+
+  benchmark:
+    name: Benchmark
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Use Node.js
+        uses: actions/setup-node@v4
+        with:
+          cache: "npm"
+      - name: Install dependencies
+        run: npm install --ignore-scripts --no-audit --no-fund
+      - name: Run benchmarks
+        uses: CodSpeedHQ/action@v2
+        with:
+          token: ${{ secrets.CODSPEED_TOKEN }}
+          run: node benchmarks/benchmarks.js

benchmarks/benchmarks.js

@@ -0,0 +1,18 @@
+import { Bench } from "tinybench";
+import { withCodSpeed } from "@codspeed/tinybench-plugin";
+import * as fs from "fs";
+import { format } from '../index.js'
+
+let filelist = fs.readdirSync('./benchmarks/__fixtures__')
+
+let bench = withCodSpeed(new Bench())
+
+for (let filename of filelist) {
+	let css = fs.readFileSync(`./benchmarks/__fixtures__/${filename}`, 'utf8')
+	let byte_size = (Buffer.byteLength(css) / 1024).toFixed(1)
+	bench.add(`${filename} (${byte_size}kB)`, () => format(css))
+}
+
+await bench.run()
+
+console.table(bench.table())