From 275215f7bcdcba82ad3d4227ef65b3213de2fe7a Mon Sep 17 00:00:00 2001
From: Joyee Cheung <joyeec9h3@gmail.com>
Date: Mon, 10 Nov 2025 13:39:08 +0100
Subject: [PATCH] benchmark: use typescript for import cjs benchmark

The original benchmark uses a not very realistic fixture (it has
a huge try-catch block that would throw on the first line and then
export at the end, hardly representative of real-world code).
Also, it measures the entire import including evaluation, not just
parsing. This updates the name to import-cjs to be more accurate,
and use the typescript.js as the fixture which has been reported
to be slow to import, leading users to use require() to work around
the peformance impact. It splits the measurement into two different
types: parsing CJS for the first time (where the overhead of
loading the lexer makes a difference) and parsing CJS after the
lexer has been loaded.

PR-URL: https://github.com/nodejs/node/pull/60663
Refs: https://github.com/nodejs/node/issues/59913
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
---
 benchmark/esm/cjs-parse.js  | 39 -----------------------------------
 benchmark/esm/import-cjs.js | 41 +++++++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 39 deletions(-)
 delete mode 100644 benchmark/esm/cjs-parse.js
 create mode 100644 benchmark/esm/import-cjs.js

diff --git a/benchmark/esm/cjs-parse.js b/benchmark/esm/cjs-parse.js
deleted file mode 100644
index 13516a93133..00000000000
--- a/benchmark/esm/cjs-parse.js
+++ /dev/null
@@ -1,39 +0,0 @@
-'use strict';
-const fs = require('fs');
-const path = require('path');
-const common = require('../common.js');
-const { strictEqual } = require('assert');
-
-const tmpdir = require('../../test/common/tmpdir');
-const benchmarkDirectory = tmpdir.resolve('benchmark-esm-parse');
-
-const bench = common.createBenchmark(main, {
-  n: [1e2],
-});
-
-async function main({ n }) {
-  tmpdir.refresh();
-
-  fs.mkdirSync(benchmarkDirectory);
-
-  let sampleSource = 'try {\n';
-  for (let i = 0; i < 1000; i++) {
-    sampleSource += 'sample.js(() => file = /test/);\n';
-  }
-  sampleSource += '} catch {}\nexports.p = 5;\n';
-
-  for (let i = 0; i < n; i++) {
-    const sampleFile = path.join(benchmarkDirectory, `sample${i}.js`);
-    fs.writeFileSync(sampleFile, sampleSource);
-  }
-
-  bench.start();
-  for (let i = 0; i < n; i++) {
-    const sampleFile = path.join(benchmarkDirectory, `sample${i}.js`);
-    const m = await import('file:' + sampleFile);
-    strictEqual(m.p, 5);
-  }
-  bench.end(n);
-
-  tmpdir.refresh();
-}
diff --git a/benchmark/esm/import-cjs.js b/benchmark/esm/import-cjs.js
new file mode 100644
index 00000000000..e3d4e19e476
--- /dev/null
+++ b/benchmark/esm/import-cjs.js
@@ -0,0 +1,41 @@
+'use strict';
+const common = require('../common.js');
+const assert = require('assert');
+const tmpdir = require('../../test/common/tmpdir');
+const fixtures = require('../../test/common/fixtures.js');
+const fs = require('fs');
+
+// This fixture has 2000+ exports.
+const fixtureFile = fixtures.path('snapshot', 'typescript.js');
+// This is fixed - typescript.js is slow to load, so 10 is enough.
+// And we want to measure either 10 warm loads, or 1 cold load (but compare.js would run it many times)
+const runs = 10;
+const bench = common.createBenchmark(main, {
+  type: ['cold', 'warm'],
+}, {
+  setup() {
+    tmpdir.refresh();
+    fs.cpSync(fixtureFile, tmpdir.resolve(`imported-cjs-initial.js`));
+    for (let i = 0; i < runs; i++) {
+      fs.cpSync(fixtureFile, tmpdir.resolve(`imported-cjs-${i}.js`));
+    }
+  },
+});
+
+async function main({ type }) {
+  if (type === 'cold') {
+    bench.start();
+    await import(tmpdir.fileURL(`imported-cjs-initial.js`));
+    bench.end(1);
+  } else {
+    await import(tmpdir.fileURL(`imported-cjs-initial.js`));  // Initialize the wasm first.
+    bench.start();
+    let result;
+    for (let i = 0; i < runs; i++) {
+      result = await import(tmpdir.fileURL(`imported-cjs-${i}.js`));
+    }
+    bench.end(runs);
+    const mod = require(fixtures.path('snapshot', 'typescript.js'));
+    assert.deepStrictEqual(Object.keys(mod), Object.keys(result.default));
+  }
+}