Peer Dependencies
Peer dependencies are a concept in package management, particularly in Node.js and npm, that specify packages that a library or tool expects to be installed by the consuming application rather than bundled directly. They indicate that a package is compatible with a specific version of another package but does not include it as a direct dependency. This helps avoid version conflicts and duplication when multiple packages depend on the same shared library.
Developers should use peer dependencies when creating libraries, plugins, or tools that need to share a common dependency with the host application, such as React components, Angular modules, or Babel plugins. This ensures that only one version of the shared dependency is installed in the final application, preventing issues like multiple instances of React causing errors. It's essential for maintaining compatibility and reducing bundle size in modular ecosystems.