lib: add afterEach hook option to each benchmark

lib/clock.js

@@ -111,6 +111,7 @@ let i = 0;
 let ${varNames.context} = {};
 `;
 
+	const hasAfterEach = !!bench.afterEach;
 	let benchFnCall = `${awaitOrEmpty}${varNames.bench}.fn()`;
 	const wrapFunctions = [];
 	for (const p of bench.plugins) {
@@ -126,11 +127,17 @@ let ${varNames.context} = {};
 		return `${n}(${prev})`;
 	}, benchFnCall);
 
+	let awaitOrEmptyAfterEach = "";
+	if (hasAfterEach && types.isAsyncFunction(bench.afterEach)) {
+		awaitOrEmptyAfterEach = "await ";
+	}
 	code += `
 const startedAt = ${varNames.timer}.now();
 
-for (; i < count; i++)
+for (; i < count; i++) {
   ${benchFnCall};
+  ${hasAfterEach ? `${awaitOrEmptyAfterEach}${varNames.bench}.afterEach();` : ""}
+}
 
 const duration = Number(${varNames.timer}.now() - startedAt);
 `;

lib/index.js

@@ -34,13 +34,14 @@ class Benchmark {
 	plugins;
 	repeatSuite;
 
-	constructor(name, fn, minTime, maxTime, plugins, repeatSuite) {
+	constructor(name, fn, { minTime, maxTime, plugins, repeatSuite, afterEach }) {
 		this.name = name;
 		this.fn = fn;
 		this.minTime = minTime;
 		this.maxTime = maxTime;
 		this.plugins = plugins;
 		this.repeatSuite = repeatSuite;
+		this.afterEach = afterEach;
 
 		this.hasArg = this.fn.length >= 1;
 		if (this.fn.length > 1) {
@@ -130,14 +131,23 @@ class Suite {
 		}
 		validateFunction(fn, "fn");
 
-		const benchmark = new Benchmark(
-			name,
-			fn,
-			options.minTime,
-			options.maxTime,
-			this.#plugins,
-			options.repeatSuite,
-		);
+		// Validate afterEach usage with workers
+		if (options.afterEach) {
+			validateFunction(options.afterEach, "options.afterEach");
+			if (this.#useWorkers) {
+				throw new Error(
+					`The "afterEach" hook is not supported when using Worker Threads. Remove "afterEach" from the benchmark "${name}" or set "useWorkers: false".`,
+				);
+			}
+		}
+
+		const benchmark = new Benchmark(name, fn, {
+			minTime: options.minTime,
+			maxTime: options.maxTime,
+			plugins: this.#plugins,
+			repeatSuite: options.repeatSuite,
+			afterEach: options.afterEach,
+		});
 		this.#benchmarks.push(benchmark);
 		return this;
 	}

test/fixtures/cached.js

@@ -0,0 +1,3 @@
+module.exports = {
+	foo: "bar",
+};

test/hooks.js

@@ -0,0 +1,72 @@
+const { describe, it } = require("node:test");
+const assert = require("node:assert");
+const path = require("node:path");
+const { Suite } = require("../lib/index");
+
+describe("afterEach hook", () => {
+	it("should call afterEach after every iteration in unmanaged benchmarks", async () => {
+		let afterEachCallCount = 0;
+		const suite = new Suite({ reporter: () => {} });
+
+		suite.add(
+			"unmanaged with afterEach",
+			{
+				afterEach: () => {
+					afterEachCallCount++;
+				},
+			},
+			() => {
+				const sum = 1 + 2; // Benchmark logic
+				return sum;
+			},
+		);
+
+		await suite.run();
+
+		// Validate afterEach was called correctly
+		assert.ok(afterEachCallCount > 0, "afterEach was not called");
+	});
+
+	it("should be called after each iteration of a benchmark", async () => {
+		const suite = new Suite({ reporter: () => {} });
+		const cachedModule = path.resolve(
+			path.join(__dirname, "./fixtures/cached.js"),
+		);
+
+		suite.add(
+			"unmanaged with afterEach",
+			{
+				afterEach: () => {
+					delete require.cache[cachedModule];
+				},
+			},
+			() => {
+				assert.ok(require.cache[cachedModule] === undefined);
+				require(cachedModule);
+				assert.ok(require.cache[cachedModule] !== undefined);
+			},
+		);
+
+		await suite.run();
+		assert.ok(require.cache[cachedModule] === undefined);
+	});
+
+	it("should throw error when afterEach is used with Worker Threads", () => {
+		const suite = new Suite({ reporter: () => {}, useWorkers: true });
+
+		assert.throws(() => {
+			suite.add(
+				"worker with afterEach",
+				{
+					afterEach: () => {
+						console.log("This will fail");
+					},
+				},
+				() => {
+					const result = 42; // Some logic
+					return result;
+				},
+			);
+		}, /The "afterEach" hook is not supported when using Worker Threads/);
+	});
+});

test/plugin-api-doc.js

@@ -67,7 +67,7 @@ describe("plugin API", async () => {
       "getReport(string)",
       "getResult(string)",
       "isSupported()",
-      "onCompleteBenchmark([number, number, object], {fn, fnStr, hasArg, isAsync, maxTime, minTime, name, plugins, repeatSuite})",
+      "onCompleteBenchmark([number, number, object], {afterEach, fn, fnStr, hasArg, isAsync, maxTime, minTime, name, plugins, repeatSuite})",
       "toJSON(string)",
       "toString()",
     ]);