CommonJSlike

CommonJSlike is a term used to describe module systems or module patterns in JavaScript that resemble the CommonJS specification, without implying full conformance to the official standard. It refers to environments or toolchains that provide a CommonJS-like API, typically including a require function for loading modules and a module.exports or exports object for exporting values. The label emphasizes compatibility and familiar semantics rather than formal compliance.

Key features commonly associated with CommonJSlike systems include a synchronous loading model via require, per-file module scope, and a simple module cache so that a module is executed only once. In many implementations, each file is treated as a separate module, with a module object containing id, exports, and other metadata. The exports alias is often used to attach the public API of a module.

CommonJSlike patterns are widespread in JavaScript environments that run outside Node.js, such as browsers, through bundlers like Browserify, Webpack, and Parcel. These tools bundle modules written with CommonJS-like syntax into a format suitable for browsers, sometimes with additional features or polyfills, and may also interoperate with other module systems.

Differences from the official CommonJS specification can include variations in feature sets, resolution rules, and environment-specific limitations. Some CommonJSlike environments support only a subset of CommonJS features, or implement additional globals and shims (for example, process or __dirname). As the JavaScript ecosystem has shifted toward ES modules, the prevalence of strict CommonJSlike implementations has diminished, but many legacy projects still rely on them.

In practice, CommonJSlike is often used to describe Node-style module usage in non-Node contexts, or to differentiate informal, CommonJS-inspired patterns from native ES module syntax.