Why might `require()` or `import` throw an `ENOENT` error, and how to fix it?

`require()` or `import` can throw an `ENOENT` error when: 1. **Module Not Found:** The specified module path (e.g., `require('./myModule.js')` or `import myModule from './myModule'`) does not point to an existing file or directory containing an `index.js` or `package.json` with a `main` entry. 2. **Node Module Missing:** You're trying to `require('some-npm-package')`, but it hasn't been installed (`npm install`) or is missing from `node_modules`. 3. **Incorrect Path:** The relative path used is incorrect from the perspective of the calling file. **Fixes:** * **Verify Path:** Ensure the path passed to `require()` or `import` is correct. Use `path.join(__dirname, 'path/to/module')` for relative paths within the same project. * **Install Dependencies:** If it's an NPM package, run `npm install` to ensure `node_modules` is up-to-date. * **Check `package.json`:** For local modules, ensure `package.json` (if present) correctly specifies the `main` entry point. * **File Extensions:** Explicitly adding `.js` (e.g., `require('./myModule.js')`) can sometimes clarify issues, especially with ES Modules.