chore: add a benchmark comparing the performance of functions created with the expression parser with native JS functions

Author: josdejong

test/benchmark/expression_parser_functions.js

@@ -0,0 +1,30 @@
+// test performance of plain JS functions vs custom functions defined via the expression parser
+
+import assert from 'node:assert'
+import { Bench } from 'tinybench'
+import { all, create } from '../../lib/esm/index.js'
+import { formatTaskResult } from './utils/formatTaskResult.js'
+
+const math = create(all)
+
+const cubeJsPlain = (x) => x * x * x
+const cubeJsWithMathjs = (x) => math.multiply(x, math.multiply(x, x))
+const cubeMathjsExpr = math.evaluate('f(x) = x * x * x')
+
+assert.strictEqual(cubeJsPlain(3), 27)
+assert.strictEqual(cubeJsWithMathjs(3), 27)
+assert.strictEqual(cubeMathjsExpr(3), 27)
+
+const bench = new Bench({ time: 100, iterations: 1000 })
+  .add('cubeJsPlain', function () {
+    cubeJsPlain(3)
+  })
+  .add('cubeJsWithMathjs', function () {
+    cubeJsWithMathjs(3)
+  })
+  .add('cubeMathjsExpr', function () {
+    cubeMathjsExpr(3)
+  })
+
+bench.addEventListener('cycle', (event) => console.log(formatTaskResult(bench, event.task, 3)))
+await bench.run()

test/benchmark/utils/formatTaskResult.js

@@ -5,15 +5,16 @@ const varianceWidth = 8
  * Format a result like "Task name   2.30 µs ±0.79%"
  * @param {import('tinybench').Bench} bench
  * @param {import('tinybench').Task} task
+ * @param {number} [digits]
  * @return {string}
  */
-export function formatTaskResult (bench, task) {
+export function formatTaskResult (bench, task, digits = 2) {
   const nameWidth = Math.max(...bench.tasks.map(task => task.name.length)) + 1
 
   const name = task.name
   const { variance, mean } = task.result.latency
 
-  const meanStr = `${(mean * 1000).toFixed(2)} \u00b5s`
+  const meanStr = `${(mean * 1000).toFixed(digits)} \u00b5s`
   const varianceStr = `±${((variance / mean) * 100).toFixed(2)}%`
   return `${padRight(name, nameWidth)} ${padLeft(meanStr, durationWidth)} ${padLeft(varianceStr, varianceWidth)}`
 }