feat: throw error if provided hooks are not functions (#390)

Author: Uzlopak

src/task.ts

@@ -24,6 +24,8 @@ import {
   toError,
 } from './utils'
 
+const hookNames = ['afterAll', 'beforeAll', 'beforeEach', 'afterEach'] as const
+
 /**
  * A class that represents each benchmark task in Tinybench. It keeps track of the
  * results, name, the task function, the number times the task function has been executed, ...
@@ -94,6 +96,15 @@ export class Task extends EventTarget {
     this.#async = fnOpts.async ?? isFnAsyncResource(fn)
     this.#signal = fnOpts.signal
 
+    for (const hookName of hookNames) {
+      if (this.#fnOpts[hookName] != null) {
+        invariant(
+          typeof this.#fnOpts[hookName] === 'function',
+          `'${hookName}' must be a function if provided`
+        )
+      }
+    }
+
     if (this.#signal) {
       this.#signal.addEventListener(
         'abort',
@@ -264,7 +275,7 @@ export class Task extends EventTarget {
     time: number,
     iterations: number
   ): Promise<{ error: Error, samples?: never } | { error?: never, samples?: Samples }> {
-    if (this.#fnOpts.beforeAll != null) {
+    if (this.#fnOpts.beforeAll) {
       try {
         await this.#fnOpts.beforeAll.call(this, mode)
       } catch (error) {
@@ -350,7 +361,7 @@ export class Task extends EventTarget {
     time: number,
     iterations: number
   ): { error: Error, samples?: never } | { error?: never, samples?: Samples } {
-    if (this.#fnOpts.beforeAll != null) {
+    if (this.#fnOpts.beforeAll) {
       try {
         const beforeAllResult = this.#fnOpts.beforeAll.call(this, mode)
         invariant(
@@ -370,7 +381,7 @@ export class Task extends EventTarget {
         return
       }
       try {
-        if (this.#fnOpts.beforeEach != null) {
+        if (this.#fnOpts.beforeEach) {
           const beforeEachResult = this.#fnOpts.beforeEach.call(this, mode)
           invariant(
             !isPromiseLike(beforeEachResult),
@@ -383,7 +394,7 @@ export class Task extends EventTarget {
         samples.push(taskTime)
         totalTime += taskTime
       } finally {
-        if (this.#fnOpts.afterEach != null) {
+        if (this.#fnOpts.afterEach) {
           const afterEachResult = this.#fnOpts.afterEach.call(this, mode)
           invariant(
             !isPromiseLike(afterEachResult),
@@ -406,7 +417,7 @@ export class Task extends EventTarget {
       return { error: toError(error) }
     }
 
-    if (this.#fnOpts.afterAll != null) {
+    if (this.#fnOpts.afterAll) {
       try {
         const afterAllResult = this.#fnOpts.afterAll.call(this, mode)
         invariant(

test/hooks-errors.test.ts

@@ -1,6 +1,6 @@
 import { expect, test } from 'vitest'
 
-import { Bench } from '../src'
+import { Bench, FnHook } from '../src'
 
 test.each(['warmup', 'run'])('%s error handling (async)', async mode => {
   const bench = new Bench({ warmup: mode === 'warmup' })
@@ -84,6 +84,36 @@ test.each(['warmup', 'run'])('%s error handling (sync)', mode => {
   expect(bazTask.result.error).toStrictEqual(error)
 })
 
+test('throw error when hooks are provided with no functions', () => {
+  const bench = new Bench()
+
+  const notAFunction = new Error('Not a function') as unknown as FnHook
+
+  expect(() => {
+    bench.add('test', () => 1, {
+      beforeAll: notAFunction
+    })
+  }).toThrowError(new Error("'beforeAll' must be a function if provided"))
+
+  expect(() => {
+    bench.add('test', () => 1, {
+      beforeEach: notAFunction
+    })
+  }).toThrowError(new Error("'beforeEach' must be a function if provided"))
+
+  expect(() => {
+    bench.add('test', () => 1, {
+      afterAll: notAFunction
+    })
+  }).toThrowError(new Error("'afterAll' must be a function if provided"))
+
+  expect(() => {
+    bench.add('test', () => 1, {
+      afterEach: notAFunction
+    })
+  }).toThrowError(new Error("'afterEach' must be a function if provided"))
+})
+
 test('hooks error handling (async)', async () => {
   const bench = new Bench()