Node.js 24.15.0 LTS: how to test stable require(esm) and compile cache without breaking your app

Short version: Node.js 24.15.0 LTS is not just another patch. The important part is that require(esm) and module compile cache are now stable, which means you can move experiments into a real rollout plan instead of living in “it seems to work” mode.

What changed

In a mixed codebase, the hardest problems are often not in the business logic, but at the boundary between CommonJS and ES Modules. That is where weird imports, CLI crashes, and build surprises usually show up.

Node.js 24.15.0 removes some of that uncertainty:

• require(esm) is stable;
• module compile cache is stable;
• so you can plan safe enablement instead of only doing local experiments.

Why it matters

For a team, that means three things:

• less pain during CJS and ESM migration,
• faster cold starts in some workflows,
• better predictability in dev, CI, and production.

It is especially useful where you have:

• lots of CLI scripts,
• tests that start hundreds of times,
• build tools that constantly load modules,
• older code that you cannot rewrite to ESM in one go.

How to do it

1. Map where your stack is mixed

Start from reality, not the architecture slide:

• where CommonJS still exists;
• where ES Modules are already used;
• which scripts run directly through node;
• what executes in CI every day.

If your project is already pure ESM, the gain may be smaller. If the codebase is old and mixed, these features matter more.

2. Start on staging, not production

Upgrade Node.js 24.15.0 on staging and run:

• unit tests,
• integration tests,
• CLI scripts,
• build,
• a smoke test for app startup.

Only after that should you move further.

3. Enable require(esm) in a narrow scope first

Do not rewrite the whole project at once. Pick 1-2 places where require(esm) actually simplifies the code, and test those paths separately.

Example:

// commonjs-entry.cjs
const mod = require('./esm-module.mjs')
console.log(mod)

The real question is simple: does it start where you expect, and does the old import path still work?

4. Test compile cache where repeated starts matter

Compile cache gives the best value where code starts often:

• CLI tools,
• tests,
• short scripts,
• dev loops,
• build jobs.

If you have one long-running server, the gain may be modest. If you have hundreds of short runs, the effect is much easier to feel.

5. Keep a simple smoke checklist

After the upgrade, check:

• server startup;
• CLI startup;
• tests;
• build;
• CJS and ESM imports;
• cold start time.

If something fails, do not switch the new behavior on in production just because the PR is already done. Roll back first, then narrow the scope.

Common mistakes

• Turning everything on at once. Then you do not know what actually broke the runtime.
• Testing only the server, not the scripts. Tooling often breaks before the app does.
• Ignoring CI. Locally it works, but the pipeline uses a different start path.
• Confusing stable features with stable app behavior. Stable in Node.js does not mean your imports are safe without testing.

Conclusion

Node.js 24.15.0 LTS should be treated as a real rollout release, not just another update. If you have a mixed CJS/ESM project, the safest path is simple: staging first, a narrow require(esm) test, a separate smoke test for compile cache, and only then broader enablement.

Official sources:

• https://nodejs.org/en/blog/release/v24.15.0
• https://nodejs.org/docs/latest-v24.x/api/modules.html#loading-esm-modules-using-require
• https://nodejs.org/docs/latest-v24.x/api/module.html#module-compile-cache
• https://nodejs.org/docs/latest-v24.x/api/cli.html