Preact with Bun

[jennydaman]

I would like to share my experience using Preact with Bun. In summary:

• ✅ bun build can replace vite build
• 🚧 bun run can replace vite, but HMR does not work.
• 🚧 bun test can replace vitest, but it does not work when dependencies use React.

In general, setup is easy and pure Preact components "just work."

import { expect, test } from "bun:test";
import { signal } from "@preact/signals";
import { fireEvent, render } from "@testing-library/preact";

const count = signal(0);

function increment() {
  count.value++;
}

function Counter() {
  return (
    <button type="button" onClick={increment}>
      click me
    </button>
  );
}

test("Counter", () => {
  const { getByText } = render(<Counter />);
  expect(count.value).toBe(0);
  fireEvent.click(getByText("click me"));
  expect(count.value).toBe(1);
});

For more information:

• https://chrisproject.org/blog/2025/08/03/preact-tooling
• https://chrisproject.org/blog/2025/08/04/preact-testing