Running ESBuild in the Browser

So, I found out the other day that it's possible to run ESBuild – that tool you usually use for bundling Javascript and Typescript code (used by Vite and Snowpack) – in the browser!

There is a package called esbuild-wasm, which contains a WebAssembly binary version of the bundler, meaning you can invoke it in the browser with a few lines of code:

import * as esbuild from "esbuild-wasm";

await esbuild.initialize({
	worker: true,
	wasmURL: "",

const result = await esbuild.transform(code, options);

This allows you to do really fun things, like building an online Javascript notebooks application!

Using the ESBuild plugins infrastructure, you can easily extend it to allow dynamic imports from HTTP sources, which is quite cool for building an online code preview tool.

I really enjoyed playing around with this, and can't wait to find ways to use my new notebooks tool - here's a quick example of what it can be used for: comparing available CRC32 libraries.