Micro optimizations, add benchmark script

bench.mts

@@ -0,0 +1,43 @@
+import "./build.mts";
+
+import fs from "node:fs";
+
+import enhancedResolve from "enhanced-resolve";
+import { bench, run } from "mitata";
+import resolve from "resolve";
+
+import { resolveSync as resolveSyncMarko } from "./dist/index.mjs";
+
+const testFromDir = process.cwd();
+const testFrom = `${testFromDir}/test.js`;
+
+bench("resolve-sync (marko)", () => {
+  resolveSyncMarko(getModuleName(), { from: testFrom });
+});
+
+bench("resolve (browserify ish)", () => {
+  resolve.sync(getModuleName(), { basedir: testFromDir });
+});
+
+const enhancedResolver = enhancedResolve.create.sync({
+  extensions: [".js", ".json"],
+  conditionNames: ["default", "node", "import", "require"],
+});
+bench("enhanced-resolve (webpack)", () => {
+  enhancedResolver(testFromDir, getModuleName());
+});
+
+try {
+  await run();
+} finally {
+  fs.rmSync(`${testFromDir}/node_modules/@_`, { recursive: true, force: true });
+}
+
+function getModuleName() {
+  const name = `@_/${Math.trunc(Math.random() * Number.MAX_SAFE_INTEGER).toString(36)}`;
+  const moduleDir = `${testFromDir}/node_modules/${name}`;
+  fs.mkdirSync(moduleDir, { recursive: true });
+  fs.writeFileSync(`${moduleDir}/index.js`, "");
+  fs.writeFileSync(`${moduleDir}/package.json`, "{}");
+  return name;
+}

package.json

@@ -45,6 +45,7 @@
     "@ci:release": "npm run build && changeset publish && npm ci",
     "@ci:test": "c8 npm test -- --forbid-pending --forbid-only",
     "@ci:version": "npm run build && npm run format && changeset version && npm i --package-lock-only",
+    "bench": "tsx ./bench.mts",
     "build": "tsc -b && tsx build.mts",
     "change": "changeset add",
     "format": "eslint --format unix --fix .; prettier . --write --log-level=warn",
@@ -61,10 +62,13 @@
     "@changesets/changelog-github": "^0.5.1",
     "@changesets/cli": "^2.29.5",
     "@eslint/js": "^9.29.0",
+    "@mitata/counters": "^0.0.8",
     "@types/mocha": "^10.0.10",
     "@types/node": "^24.0.5",
+    "@types/resolve": "^1.20.6",
     "c8": "^10.1.3",
     "cross-env": "^7.0.3",
+    "enhanced-resolve": "^5.18.2",
     "esbuild": "^0.25.5",
     "eslint": "^9.29.0",
     "eslint-formatter-unix": "^8.40.0",
@@ -73,10 +77,12 @@
     "globals": "^16.2.0",
     "husky": "^9.1.7",
     "lint-staged": "^16.1.2",
+    "mitata": "^1.0.34",
     "mocha": "^11.7.1",
     "mocha-snap": "^5.0.0",
     "prettier": "^3.6.2",
     "prettier-plugin-packagejson": "^2.5.16",
+    "resolve": "^1.22.10",
     "tsx": "^4.20.3",
     "typescript": "^5.8.3",
     "typescript-eslint": "^8.35.0"

src/index.ts

@@ -78,15 +78,14 @@
 }
 
 function resolveId(ctx: ResolveContext, id: string) {
-  if (id[0] === "#") {
-    return resolveSubImport(ctx, ctx.fromDir, id);
+  switch (id[0]) {
+    case ".":
+      return resolveRelative(ctx, ctx.fromDir, id);
+    case "#":
+      return resolveSubImport(ctx, ctx.fromDir, id);
+    default:
+      return resolvePkg(ctx, id);
   }
-
-  if (/^\.\.?(?:\/|$)/.test(id)) {
-    return resolveRelative(ctx, ctx.fromDir, id);
-  }
-
-  return resolvePkg(ctx, id);
 }
 
 function resolveRelative(ctx: ResolveContext, dir: string, id: string) {
@@ -144,8 +143,24 @@
 }
 
 function resolvePkg(ctx: ResolveContext, id: string) {
-  const [, name, part] = /^((?:@[^/]+\/)?[^/]+)(.*)$/.exec(id)!;
   let dir = ctx.fromDir;
+  let slash = id.indexOf("/");
+  let name = id;
+  let part = "";
+
+  if (slash !== -1) {
+    if (id[0] !== "@") {
+      name = id.slice(0, slash);
+      part = id.slice(slash);
+    } else {
+      slash = id.indexOf("/", slash + 1);
+      if (slash !== -1) {
+        name = id.slice(0, slash);
+        part = id.slice(slash);
+      }
+    }
+  }
+
   do {
     const resolved = resolvePkgPart(ctx, dir + "/node_modules/" + name, part);
     if (resolved !== undefined) return resolved;