Fix · Node, npm and build

"Cannot use import statement outside a module" or ERR_REQUIRE_ESM

What you may see

A script fails on the first import line
A package says it is an ES module

Most likely cause

Node has two module styles (import and require) and the file or package uses the one that does not match the settings.

Check first (about two minutes)

Does your package.json have "type": "module"? Is the file .js, .mjs or .cjs?

The fix prompt

What you type here never leaves your browser. The search runs on this page, and nothing is sent to a server or to an AI.

The exact error or what you see

What you did before it happened

Kept only in this browser, on this device. Keys and passwords are removed before anything is saved.

Prompt language

You are a patient senior engineer who knows Node.js, npm and build tools and explains them to people who are not developers. I am not a developer, so explain every step in plain words and tell me exactly which button, menu or command you mean. If you are not sure about something, say so; do not guess.

THE PROBLEM
"Cannot use import statement outside a module" or ERR_REQUIRE_ESM

THE EXACT ERROR OR WHAT I SEE
[paste the exact error here]

WHAT I DID BEFORE IT HAPPENED
[write in a few words what you did before it happened]

MOST LIKELY CAUSE
Node has two module styles (import and require) and the file or package uses the one that does not match the settings.

DO THESE STEPS, IN THIS ORDER
1. Show the top of the failing file, package.json type, and how the script is started.
2. Choose ONE style for the project and make the file match: rename to .mjs, or set "type", or use dynamic import() for a package that is ES-only.
Stop and tell me if what you see does not match a step. Do not skip ahead.

CHECK THAT IT WORKED
- The script runs and prints its normal output.
Tell me exactly what I should see on the screen when it works.

DO NOT CHANGE
- Do not convert all files at once.
- Anything I did not ask about: the design, the text, other pages, other settings or the data.
- Do not delete files, data or branches, do not reset or force-push, and do not rewrite history, unless you first show me exactly what would be lost and I say yes.
- Do not paste, print or ask me to paste a password or secret key into this chat. If one is needed, tell me which settings page of the right service to store it in.

WHEN YOU FINISH
Explain in simple words what you changed (file by file or setting by setting), why you changed it, and how I can undo it.

Paste it into Claude, ChatGPT, Gemini or Cursor, then follow what it says.

After you tried it, did it work?

Steps

Show the top of the failing file, package.json type, and how the script is started.
Choose ONE style for the project and make the file match: rename to .mjs, or set "type", or use dynamic import() for a package that is ES-only.

Do not do this

Do not mix require and import in the same file.
Do not convert all files at once.

Try another entry