[Feature Request]: code splitting with commonjs

[DylanPiercey]

I'm playing around with using esbuild for bundling library code with a setup like the following:

import { build } from "esbuild";

await build({
  external: [...], // Make node_modules external
  bundle: true,
  format: "esm",
  splitting: true,
  platform: "node",
  entryPoints: [
    "src/entry-a.ts",
    "src/entry-b.ts"
  ],
});

The problem is many libraries I work on require exposing multiple "entry point" files to the user. Think stuff like:

import a from "some-module/entry-a";
import b from "some-module/entry-b";

With the esm output it seems I can easily achieve this with the code splitting automatically deduping common code between the entries.

Currently though it's not possible to use format: "cjs" with splitting enabled. It would be great if this was possible because then it would allow me to use esbuild for these modules which require backward compat via providing cjs and esm builds.

If I run esbuild again on the output from the esm build with format: "cjs" it basically does what I want, however it re-inlines all of the runtime stuff again which isn't ideal.

[evanw]

This happens because the code splitting feature is not finished yet. Closing as a duplicate of #16.