Bundling and WebAssembly

chelabase functions deploy and dev build each function into one bundle: a JSON manifest of modules (JavaScript, WebAssembly, text and data) with the compatibility date and flags, uploaded to the branch and identified by its SHA-256. Deployments are immutable; a deploy adds one and makes it active, and rollback makes an earlier one active again.

esbuildCopy Anchor Link

The CLI runs esbuild from the project (node_modules/.bin/esbuild), else from PATH. If neither exists the command exits non-zero and says to run:

npm install --save-dev esbuild

It bundles the entry as an ES module (--format=esm --bundle --platform=neutral --conditions=workerd,worker,browser), so packages resolve the way they do for Cloudflare Workers. The runtime offers Workers' standard APIs, not Node's.

WebAssemblyCopy Anchor Link

Import a core WebAssembly module with a ./ path; the CLI keeps the import external and ships the file as a wasm module:

import add from "./add.wasm";

export default {
  async fetch(): Promise<Response> {
    const { exports } = new WebAssembly.Instance(add);
    return Response.json({ sum: (exports.add as (a: number, b: number) => number)(2, 3) });
  },
};

• Core modules only. import x from "./x.wasm" gives a compiled WebAssembly.Module; instantiate it with new WebAssembly.Instance(module, imports).

• WebAssembly.instantiate(bytes) is refused ("Wasm code generation disallowed by embedder"): the runtime does not compile raw bytes. Ship the file as a module import.

• WASI components (a .wasm whose header marks it a component) are converted first with jco transpile, and the transpiled output is bundled. This needs jco and the preview2 shim; without them the command stops and says to run:

  Copy Text

  npm install --save-dev @bytecodealliance/jco @bytecodealliance/preview2-shim

LimitsCopy Anchor Link

Unused bundles are cleaned up hourly: a bundle that no deployment of any branch refers to (rollback deployments count) and that is older than an hour is deleted, and a deleted database's bundles go with it.