fix: compatibility with commonjs

tsup.config.ts

@@ -8,4 +8,28 @@ export default defineConfig({
 	format: ["esm", "cjs"],
 	outDir: "lib",
 	sourcemap: true,
+	plugins: [
+		{
+			// https://github.com/egoist/tsup/issues/953#issuecomment-2294998890
+			// ensuring that all local requires/imports in `.cjs` files import from `.cjs` files.
+			// require('./path') → require('./path.cjs') in `.cjs` files
+			// require('../path') → require('../path.cjs') in `.cjs` files
+			// from './path' → from './path.cjs' in `.cjs` files
+			// from '../path' → from '../path.cjs' in `.cjs` files
+			name: "fix-cjs-imports",
+			renderChunk(code) {
+				if (this.format === "cjs") {
+					const regexCjs =
+						/require\((?<quote>['"])(?<import>\.[^'"]+)\.js['"]\)/g;
+					const regexEsm =
+						/from(?<space>[\s]*)(?<quote>['"])(?<import>\.[^'"]+)\.js['"]/g;
+					return {
+						code: code
+							.replace(regexCjs, "require($<quote>$<import>.cjs$<quote>)")
+							.replace(regexEsm, "from$<space>$<quote>$<import>.cjs$<quote>"),
+					};
+				}
+			},
+		},
+	],
 });