Node "SyntaxError: Cannot use import statement outside a module" in CI

Node parsed the file as CommonJS, where import is not valid syntax. A .js file is CommonJS unless the nearest package.json sets "type": "module", or the file is renamed to .mjs.

What this error means

Running a script with top-level import fails immediately with "SyntaxError: Cannot use import statement outside a module" at the first import line.

node

import express from 'express';
^^^^^^

SyntaxError: Cannot use import statement outside a module
    at internalCompileFunction (node:internal/vm:73:18)

Common causes

The file is treated as CommonJS

A .js file with no "type": "module" in the nearest package.json is CommonJS, so import/export syntax is a parse error.

A tool ran raw .ts/.jsx through Node without transpiling

Node received source with import that a bundler or loader was supposed to compile, but the build step was skipped in CI.

How to fix it

Declare the package as ESM

Add "type": "module" so Node parses .js files as ES modules and import is valid.

package.json

{
  "type": "module"
}

Or rename the entry to .mjs

A .mjs file is always parsed as ESM regardless of package.json, which is useful for a single script.

Terminal

node ./scripts/build.mjs

How to prevent it

Decide CommonJS vs ESM per package and keep it consistent.
Run the build step in CI so transpiled output, not raw source, reaches Node.
Use .mjs/.cjs extensions to be explicit when mixing module systems.