Uncaught SyntaxError: Cannot use import statement outside a module when importing ECMAScript 6

The error message "Uncaught SyntaxError: Cannot use import statement outside a module" occurs when you try to use the ECMAScript 6 (ES6) import statement in a context that is not recognized as a module by the JavaScript runtime. Modules in JavaScript are a way to organize and encapsulate code, and they use the import and export statements to define their dependencies and interface.

Here's an example that demonstrates this error:

Suppose you have two JavaScript files:

module.js:

// module.js
export function myFunction() {
    return "Hello from myFunction!";
}

main.js:

// main.js
import { myFunction } from './module.js';
console.log(myFunction());
 
If you try to run main.js in a browser environment (for instance, by including the <script> tag in an HTML file), you'll likely encounter the "Uncaught SyntaxError: Cannot use import statement outside a module" error because browsers, by default, do not treat scripts as ES6 modules.

To fix this, you need to indicate to the JavaScript runtime that your code should be treated as a module. You can do this by using the type="module" attribute in the <script> tag when including your JavaScript file:

index.html:

<!DOCTYPE html>
<html>
<head>
    <title>ES6 Module Example</title>
</head>
<body>
    <script type="module" src="main.js"></script>
</body>
</html>

By using type="module" in the <script> tag, you tell the browser to treat the script as an ES6 module, allowing you to use the import and export statements.

Alternatively, if you're working in a Node.js environment, you can use the --experimental-modules flag to enable ES6 modules:

node --experimental-modules main.js

Remember that enabling ES6 modules might involve additional considerations, such as handling relative paths and understanding how module resolution works.

In summary, to avoid the "Uncaught SyntaxError: Cannot use import statement outside a module" error, make sure you're running your code as an ES6 module using the appropriate setup in the browser or Node.js environment.

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