How to solve “Cannot use import statement outside a module” when you cannot set module type in package.json?

I am working on a Create-React-App project (writing in normal JS (.jsx), not TypeScript for what it’s worth).

I wanted to modify some of the build files (swap out some references to local files with live ones) and found the npm package replace-in-file.

I created a .js file for this package and set up the JS for it. The only issue is that when I try to run functions from that file I get the error:

import {replaceInFile} from 'replace-in-file';
SyntaxError: Cannot use import statement outside a module

Not a problem, I just added:

"type": "module",

to my package.json file.

This worked – I no longer get the error above and my script on this file runs.

However, now Create-React-App and Storybook fail to compile and I get the error:

BREAKING CHANGE: The request ‘./my-app’ failed to resolve only because
it was resolved as fully specified (probably because the origin is
strict EcmaScript Module, e. g. a module with javascript mimetype, a
‘.mjs’ file, or a ‘.js’ file where the package.json contains
‘“type”: “module”‘).

I tried to replace import() with

const replaceInFile = require("replace-in-file");

But that doesn’t work of course.

I tried import("replace-in-file"); but that doesn’t seem to work with node (eg process.argv fails).

I also tried setting "module": "commonjs" but that still stopped Create-React-App from working.

Would anyone know how I could get both this local file/npm package and Create-React-App working within the 1 project?