CommonJS vs ES Modules: what is the difference?
Try code in the playgroundUnderstand the concept
CommonJS and ES Modules are two systems for dividing JavaScript code into reusable modules. CommonJS uses runtime require calls, while ES Modules provide standard import and export declarations with a statically described dependency structure. Their loading and interoperability rules depend on the runtime and file configuration.
Important ideas
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CommonJS uses
requireandmodule.exports. -
ES Modules use
importandexport. -
Modules are generally cached; shared module state can affect many requests.
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Node can identify ESM through
.mjsor a package'stypesetting; do not mix syntaxes blindly. -
Caching applies to resolved module identities; multiple copies or distinct module URLs may not share one instance.
Can you explain it without the notes?
CommonJS vs ES Modules: what is the difference?
Use your own words. Explain an example and one limitation before checking the explanation.
Check your explanation
CommonJS and ES Modules are two systems for dividing JavaScript code into reusable modules. CommonJS uses runtime require calls, while ES Modules provide standard import and export declarations with a statically described dependency structure. Their loading and interoperability rules depend on the runtime and file configuration.
Turn this concept into a clear answer.
- Module-level mutable state can be shared by many requests in one process, but it is not a shared store across app processes.
Adapted from 01_JAVASCRIPT_TYPESCRIPT.md · “CommonJS vs ES Modules: what is the difference?”. Examples are study fragments; framework behavior can depend on your version.