This error message:

“An import declaration can only be used at the top level of a module.”

…means that you’re trying to use an import statement inside a function, conditional block, or any non-top-level scope, which is not allowed in JavaScript ES Modules.

✅ Correct Usage (Top-Level):

// This is valid
import { readFile } from 'fs';

function readFileSync(path) {
  readFile(path, (err, data) => {
    if (err) throw err;
    console.log(data.toString());
  });
}

readFileSync('./file.txt');

❌ Incorrect Usage (Inside Function or Block):

// ❌ This will cause the error
function loadModule() {
  import { readFile } from 'fs';  // ❌ Not allowed
  readFile('./file.txt', (err, data) => {
    if (err) throw err;
    console.log(data.toString());
  });
}

🚀 How to Fix It:

1. Move import to the top level:

import { readFile } from 'fs'; 
function loadFile() { 
   readFile('./file.txt', (err, data) => { if (err) throw err; console.log(data.toString()); }); 
} 
loadFile();

1. For Dynamic Imports (if you need to import conditionally): Use the import() function (dynamic import) instead of import syntax:

async function loadModule() 
{ 
const { readFile } = await import('fs'); // ✅ Dynamic import readFile('./file.txt', (err, data) => { if (err) throw err; console.log(data.toString()); }); 
} 
loadModule();

⚠️ Key Notes:

• Ensure your file is treated as an ES Module:
  • In package.json: "type": "module"
  • Or use .mjs extension.
• Dynamic imports (import()) are supported in Node.js (v13.2.0+).