perf: bind timestamping function to their modules (#149)

Signed-off-by: Jérôme Benoit <jerome.benoit@piment-noir.org>

Author: jerome-benoit

src/utils.ts

@@ -3,9 +3,11 @@ import type { Fn, Statistics } from './types';
 
 export const nanoToMs = (nano: number) => nano / 1e6;
 
-export const hrtimeNow = () => nanoToMs(Number(process.hrtime.bigint()));
+const hrtimeBigint = process.hrtime.bigint.bind(process.hrtime);
+export const hrtimeNow = () => nanoToMs(Number(hrtimeBigint()));
 
-export const now = () => performance.now();
+const performanceNow = performance.now.bind(performance);
+export const now = performanceNow;
 
 /**
  * Checks if a value is a promise-like object.

test/index.test.ts

@@ -1,7 +1,7 @@
 import { expect, test, vi } from 'vitest';
-import { Bench, type Task } from '../src';
+import { Bench, type Task, hrtimeNow } from '../src';
 
-test('basic', async () => {
+test('now() basic', async () => {
   const bench = new Bench({ time: 100 });
   bench
     .add('foo', async () => {
@@ -36,6 +36,41 @@ test('basic', async () => {
   ).toBeCloseTo(1000, 1);
 });
 
+test('hrtimeNow() basic', async () => {
+  const bench = new Bench({ time: 100, now: hrtimeNow });
+  bench
+    .add('foo', async () => {
+      await new Promise((resolve) => setTimeout(resolve, 50));
+    })
+    .add('bar', async () => {
+      await new Promise((resolve) => setTimeout(resolve, 100));
+    });
+
+  await bench.run();
+
+  const { tasks } = bench;
+
+  expect(tasks.length).toEqual(2);
+
+  expect(tasks[0]?.name).toEqual('foo');
+  expect(tasks[0]?.result?.totalTime).toBeGreaterThan(50);
+  expect(tasks[0]?.result?.latency.mean).toBeGreaterThan(50);
+  // throughput mean is ops/s, period is ms unit value
+  expect(
+    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+    tasks[0]!.result!.throughput.mean * tasks[0]!.result!.period,
+  ).toBeCloseTo(1000, 1);
+
+  expect(tasks[1]?.name).toEqual('bar');
+  expect(tasks[1]?.result?.totalTime).toBeGreaterThan(100);
+  expect(tasks[1]?.result?.latency.mean).toBeGreaterThan(100);
+  // throughput mean is ops/s, period is ms unit value
+  expect(
+    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+    tasks[1]!.result!.throughput.mean * tasks[1]!.result!.period,
+  ).toBeCloseTo(1000, 1);
+});
+
 test('bench and task runs, time consistency', async () => {
   const bench = new Bench({ time: 100, iterations: 15 });
   bench.add('foo', async () => {