Using ECMAScript modules

ESM represents the official standard for packaging JavaScript code for reuse. ESM was introduced in ECMAScript 2015 (ES6) to bring a unified module system to the JavaScript language, a feature that was absent and in much demand for years. Unlike CommonJS (CJS) modules, which were adopted by Node.js for server-side development, ESM provides a way to statically analyze code for imports and exports, allowing for optimizations such as tree shaking, which eliminates unused code.

The introduction of ESM into the Node.js ecosystem marked a significant milestone, offering developers the benefits of a standardized module system that is compatible across different environments, including browsers, where modules can be natively loaded without the need for bundling tools.

Configuring Node.js to use ESM involves understanding and setting up project structures to accommodate the new syntax and module resolution strategy. By default, Node.js treats .js files as CJS...