Modules

Example of defining and using ES modules with import and export:

// file: mathUtils.js
export function add(a, b) {
  return a + b;
}

export const PI = 3.14159;

// file: app.js
import { add, PI } from './mathUtils.js';

console.log('Add:', add(2, 3)); // 5
console.log('PI:', PI);         // 3.14159
          

This code demonstrates:

• How to export functions and constants using export.
• How to import specific exports using import { ... } from.
• Modular code organization improving maintainability and reuse.
• The use of relative paths and the .js extension in imports.

JavaScript ES Modules provide a standard way to structure and share code across files.

• Export: Marks functions, variables, or classes as available for use in other files.
• Import: Brings in exported code from other modules.
• Supports named exports (multiple exports) and default exports (single export per file).
• Helps avoid polluting the global namespace.
• Supported natively in browsers with type="module" in script tags, and in Node.js with .mjs files or proper configuration.

• Building scalable web applications by separating concerns.
• Sharing utilities and helper functions across projects.
• Using third-party libraries and frameworks that use modules.
• Enabling tree shaking for optimized bundling.
• Facilitating code maintenance and collaboration in teams.