TypeScript

TypeScript is a first-class citizen of ESBench, ESBench's APIs are fully typed, and more than that, ESBench can execute TS files directly!

Supported Compilers

When started, ESBench installs ESM Loader Hooks to transform TS files.

When importing a TS file for the first time, ESBench will detect installed compilers by the steps:

1. If @swc/core installed, use SWC.
2. If esbuild installed, use esbuild.
3. If sucrase installed, use sucrase.
4. If typescript installed, use TypeScript.
5. No supported compiler, the import fails.

ESBench only transforms TS files and does not process other types of imports.

In the vast majority of cases where projects using TypeScript have typescript installed, this feature comes out-of-box.

Run With TypeScript

esbench.config.ts

// TypeScript config file is also supported.
import { ESBenchConfig, Executor, ProcessExecutor } from "esbench/host";

const executors: Executor[] = [new ProcessExecutor("node")];

export default { toolchains: [{ executors }] } satisfies ESBenchConfig;

benchmark/cartesian-product.ts

import { defineSuite } from "esbench";

const objectDef: Record<string, any[]> = {
	foo: [11, 22, 33, 44, 55],
	bar: ["abcdefg", "hijklmn"],
	baz: [true, false],
	qux: [1024, 2048, 4096, 8192],
};

function cartesianObject<const T extends Record<string, any[]>>(src: T) {
	const entries = Object.entries(src);
	const temp = {} as Record<string, unknown>;

	function* recursive(index: number): Iterable<unknown> {
		if (index === entries.length) {
			yield { ...temp };
		} else {
			const [key, values] = entries[index];
			for (const value of values) {
				temp[key] = value;
				yield* recursive(index + 1);
			}
		}
	}

	return recursive(0) as Iterable<Record<string, any>>;
}

function drain(generator: Iterable<unknown>) {
	// noinspection StatementWithEmptyBodyJS
	for (const _ of generator) /* No-op */;
}

export default defineSuite(scene => {
	scene.bench("cartesian", () => drain(cartesianObject(objectDef)));
});

Just run esbench, no new arguments needed, the TS loader is enabled by default.

esbench --file benchmark/cartesian-product.ts

Use in Executor

What is Executor?

ESM loader hooks only act on the current process and are not inherited by spawned processes, so new Node instances started at the executor cannot load TS suites.

To achieve the same behavior, you can use ts-directly.

import { defineConfig, ProcessExecutor } from "esbench/host";

export default defineConfig({ 
	toolchains: [{
		executors: [
			new ProcessExecutor("node --import ts-directly/register"),
		],
	}],
});

TIP

PlaywrightExecutor, WebextExecutor and WebManuallyExecutor can handle TS files automatically because ESBench intercepts their import requests.

Customize Loaders

If you prefer other TypeScript loaders (e.g. ts-node or tsx), you can disable ESBench's loader with --no-loader CLI argument:

cross-env NODE_OPTIONS="--import ts-node/esm" esbench --no-loader