fix: publish a single-file ESM bundle that Node can load (4.1.6)

[Johan Gorter (johan-gorter)]

Fixes #240.

Problem

Since 4.1.4, exports["."].import points at dist/index.js. That file comes straight from tsc and keeps its extensionless relative imports (./cache, ./dom, …), so Node, Vitest and Jest ESM all fail with ERR_MODULE_NOT_FOUND. The type declarations have the same problem: attw reported an internal resolution error for node16 and "Masquerading as ESM" for node16 from CJS.

Changes

• rollup: also emits dist/maquette.mjs (ES format, with sourcemap) from dist/index.js, next to the existing CJS and UMD bundles.
• Types: rollup-plugin-dts bundles the declarations into dist/maquette.d.mts and dist/maquette.d.cts, so ESM and CJS consumers each get correctly typed single-file declarations. This goes beyond the issue, but attw cannot pass without it.
• package.json
  • exports["."]: import → { types: maquette.d.mts, default: maquette.mjs }, require → { types: maquette.d.cts, default: maquette.cjs }.
  • Removed the browser condition, so bundlers get the ESM bundle instead of UMD. dist/maquette.umd.js / .min.js are still published for <script> use.
  • Added "sideEffects": false.
  • main and types are unchanged.
  • Version bumped to 4.1.6.
• CI: new check-package script, run at the end of npm run ci:
  • attw --pack . reports no problems for node10, node16 (CJS and ESM) and bundler.
  • tools/check-package-loads.ts packs the package, installs the tarball in a temp directory and loads it from Node through both import and require. If I point import back at dist/index.js, this check fails with the exact error from the issue.

Verification

npm run ci passes locally: lint, 95 tests, file-size check (3.65 kB gzipped), attw and the smoke test.

Follow-up

After 4.1.6 is published, remove the 4.1.3 pin and the Dependabot ignore for maquette in the Focus repo.

🤖 Generated with Claude Code

[Copilot]

🟡 Changes recommended

The lockfile still identifies the root package as version 4.1.5 rather than 4.1.6.

0 open findings

What changed in this PR

Publishes Node-compatible single-file ESM/CJS bundles with matching bundled declarations and package validation.

Changes:

• Adds ESM and declaration bundling.
• Updates package exports and release metadata.
• Adds CI package-loading and type-resolution checks.

File	Description
rollup.config.js	Adds ESM and declaration bundles.
package.json	Updates exports, scripts, dependencies, and version.
package-lock.json	Locks new tooling dependencies.
tools/​check-package-loads.ts	Smoke-tests ESM and CJS package loading.

🧠 Review effort: Balanced

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.