Analyzing Peer Dependency Changes

Peer Dependency Comparison

Peer dependencies define what versions of a package your library expects the consuming application to have installed. Changes to peer dependencies can cause installation warnings or errors.

Understanding peer dependency diffs

peerDependencies:
  ~ react: "^17.0.0 || ^18.0.0" -> "^18.0.0 || ^19.0.0"  [CHANGED]
  - react-dom: "^17.0.0 || ^18.0.0"                        [REMOVED]
  + react-dom: "^18.0.0 || ^19.0.0"                        [CHANGED]
  + @types/react: "^18.0.0 || ^19.0.0"                     [ADDED]

Why peer dependency changes matter

Scenario	Impact
Narrowed range	May exclude your project's React version
Widened range	Better compatibility, no action needed
New peer dep added	You may need to install it explicitly
Peer dep removed	One less constraint to manage

Common peer dependency issues

1. Version conflict: Two libraries require different peer dep ranges
2. Missing peer dep: npm 7+ auto-installs, npm 6 shows warnings
3. Dropped support: Library drops support for your framework version
4. Added peer dep: New requirement not present in previous version

How to use the diff for library publishing

If you maintain an npm library, compare your package.json before and after modifying peer dependencies:

• Widening ranges is a minor or patch change
• Narrowing ranges is a major change (drops compatibility)
• Adding new peer deps is a major change
• Removing peer deps is a minor change