effect.ts

import { NodeRuntime, NodeServices } from "@effect/platform-node"
import { Console, Effect, Stream } from "effect"
import { ChildProcess } from "effect/unstable/process"
import { ChildProcessSpawner } from "effect/unstable/process/ChildProcessSpawner"

Effect.gen(function*() {
  const spawner = yield* ChildProcessSpawner
  const handle = yield* spawner.spawn(ChildProcess.make`git diff`)
  yield* handle.stdout.pipe(
    Stream.decodeText,
    Stream.mkString
  )
}).pipe(
  Console.withTime("effect"),
  Effect.scoped,
  Effect.provide(NodeServices.layer),
  NodeRuntime.runMain
)

node.ts

import * as CP from "node:child_process"

async function main() {
  console.time("node")
  const handle = CP.spawn("git", ["diff"])

  handle.stdout.setEncoding("utf8")

  let out = ""
  await handle.stdout.forEach((data) => {
    out += data
  })
  console.timeEnd("node")
}

main()

results.txt

effect-smol git(main) node scratchpad/effect.ts
effect: 13.195ms

effect-smol git(main) node scratchpad/node.ts
node: 13.407ms