esm Archives | JS FAQ - JavaScript Guides Online

How to use "type": "module" in package.json

Common ECMAScript module issues include the "Cannot use import statement outside a module" error caused by missing "type":"module" in package.json or absent type="module" in script tags. Node.js requires explicit file extensions in import paths. Circular dependencies and mixing CommonJS with ESM syntax also cause runtime errors.

Node.js Core

How to enable ES modules in Node.js

Node.js Coreesm, node.js, package.json, type module

Activate ES modules in Node.js projects by adding "type": "module" to package.json. This allows .js files to be treated as ES modules, simplifying project structure. Use the exports field for entry points and ensure full file extensions in import paths. Conditional exports enable compatibility with CommonJS.

Node.js Core

How to import a module using ES modules in Node.js

Node.js Coreesm, import, js modules, node.js

Node.js distinguishes between CommonJS and ES modules using file extensions and the package.json type field. By default, .js files are CommonJS unless "type": "module" is set in package.json. The .mjs extension explicitly marks ES modules. Understanding these distinctions ensures proper module resolution and prevents errors in Node.js applications.

Modules and Imports

How to import a module in JavaScript

Modules and Importsesm, import, js modules, module

CommonJS, AMD, UMD, and ES modules each have unique advantages and drawbacks impacting JavaScript development. CommonJS simplifies server-side dependency management, while AMD enhances browser performance through asynchronous loading. ES modules offer modern syntax and optimizations like tree shaking, making them ideal for new projects. Understanding these module types is essential for effective application structure.