fix(build): Fix ESM output (#7357)

[fgnass]

Summary

This PR fixes two related issues discovered while working on ESM builds:

1. ESM builds incorrectly output CommonJS format despite being in dist/esm directories. This happens because Babel's preset-env transforms ES modules to CommonJS by default. The issue can be seen in decap-cms-core's ESM build.

2. Build dependencies are not properly configured in Nx, causing builds to fail with empty cache as packages are built in parallel without respecting dependencies.

Changes:

• Configure Babel to preserve ES modules by setting modules: false for ESM builds
• Add proper build dependencies in nx.json to ensure correct build order
• Remove direct imports from dist/esm in favor of proper package entry points

Fixes #7357

Test plan

1. Clean the workspace:

bash
npm run clean

2. Build directly with nx (this would fail before the fix):

NX_NO_CLOUD=true npx nx run decap-cms:build

3. Verify ESM output format in any package's dist/esm/index.js:

// Should see ES module syntax:
export default DecapCmsCore;
// Instead of CommonJS:
exports.default = exports.DecapCmsCore = void 0;

Checklist

• I have read the contribution guidelines.

A picture of a cute animal

[fgnass]

I noticed that the GitHub action is failing during npm install on Windows, which seems totally unrelated to the changes made by this PR. I added two further commits, which will hopefully resolve the build issue by enabling the cache option of actions/setup-node@v3 and using npm ci instead of npm install. Have you experienced similar issues with other PRs or this happening for the first time?

[martinjagodic]

@fgnass Yes, sometimes the tests fail for no reason, so we must re-run them. Thanks for the fix!

[fgnass]

Okay, the installation step now seems to work reliably, but the e2e tests failed, I guess because the files in dev-test/dist/ were missing or not correctly transferred from the build container to the one running the cypress tests. I simplified the workflow by running everything in the same container, making sure that the e2e test run only once (ubuntu / node 20.x) and not for every combination in the matrix.

[martinjagodic]

@fgnass ubuntu + node 20 is still failing

[fgnass]

I'll look into it and try to reproduce the error in my forked repo. Stay tuned.

[fgnass]

Good news: The workflow did run successfully in my forked repo: https://github.com/fgnass/decap-cms/actions/runs/12483114867/job/34838341976

I'm curious if it will succeed here too!

[dragons-library]

FWIW, I was looking at this from the decap-cms-app perspective earlier, and it currently doesn't declare it's esm export in decap-cms-app/package.json:

"module": "dist/esm/index.js",

I think it should - then you wouldn't have to update your decap-cms-app import paths.

Also, somewhat unrelated, but decap-cms-app/package.json doesn't correctly declare a dependency on decap-cms-backend-gitea, which it should for the standalone esm module to be functional:

"decap-cms-backend-gitea": "^3.1.5",

Thanks for the work on this PR, it's much more extensive than what I had explored so far.

[fgnass]

@dragons-library Good catch! I added the module field and the missing dependency.