What is the 'exports' field in package.json, and how does it improve on the older 'main' field?

Short answer

It lets you define a package's official entry points, control access to internal files, and select different outputs for CJS and ESM.

Explanation

exports prevents consumers from importing a package's internal files and supports conditions that route imports based on the runtime environment or module system (Conditional Exports).

Code example

{ "exports": { ".": { "import": "./dist/index.mjs", "require": "./dist/index.cjs" } } }

Common mistakes

• Forgetting to provide the types field or placing it in the wrong location in exports.

Follow-up questions

• How does Node.js handle circular dependencies between CJS and ESM?
• What do the ^ and ~ symbols mean in package.json, and how do they differ from an exact version?

Sources

• Node.js docs — Package entry points