fix: fix rate computation and formatting in summary

Signed-off-by: Jérôme Benoit <[email protected]>

CHANGELOG.md

@@ -8,6 +8,10 @@ and this project adheres to
 
 ## [Unreleased]
 
+### Fixed
+
+- Fix rate computation and formatting in summary.
+
 ## [0.3.2] - 2024-04-13
 
 ### Changed

src/reporter/fmt.mjs

@@ -40,3 +40,9 @@ export function errorMargin(rmoe) {
     .toLocaleString(locale)
     .replaceAll(',', "'")} %`;
 }
+
+export function speedRate(speed) {
+  return `${Number(speed.toFixed(2))
+    .toLocaleString(locale)
+    .replaceAll(',', "'")}`;
+}

src/reporter/table.mjs

@@ -1,6 +1,6 @@
 import { tatamiNgGroup } from '../constants.mjs';
 import * as clr from './clr.mjs';
-import { duration, errorMargin, iterPerSecond } from './fmt.mjs';
+import { duration, errorMargin, iterPerSecond, speedRate } from './fmt.mjs';
 
 export function size(names) {
   let size = 9;
@@ -134,16 +134,11 @@ export function summary(benchmarks, { colors = true }) {
   }`}\n  ${clr.bold(colors, clr.cyan(colors, baseline.name))}${benchmarks
     .filter(benchmark => benchmark !== baseline)
     .map(benchmark => {
-      const diff = Number(
-        ((1 / baseline.stats.avg) * benchmark.stats.avg).toFixed(2),
-      );
-      const invDiff = Number(
-        ((1 / benchmark.stats.avg) * baseline.stats.avg).toFixed(2),
-      );
-      return `\n   ${clr[1 > diff ? 'red' : 'green'](
+      const rate = (1 / baseline.stats.avg) * benchmark.stats.avg;
+      return `\n   ${clr[1 > rate ? 'red' : 'green'](
         colors,
-        1 <= diff ? diff : invDiff,
-      )}x ${1 > diff ? 'slower' : 'faster'} than ${clr.bold(
+        1 > rate ? speedRate(1 / rate) : speedRate(rate),
+      )}x ${1 > rate ? 'slower' : 'faster'} than ${clr.bold(
         colors,
         clr.cyan(colors, benchmark.name),
       )}`;

tests/formatting.js

@@ -1,6 +1,6 @@
 import { bench, group, run } from '../src/cli.mjs';
 
-group({ summary: false }, () => {
+group({ summary: true }, () => {
   bench('noop', () => {});
   bench('new Array(2 ** 0)', () => new Array(2 ** 0));
   bench('new Array(2 ** 1)', () => new Array(2 ** 1));