bun why

bun why explains why a package is installed in your project by showing the dependency chain that led to it.

Usage

bun why <package>

Arguments

• <package>: The name of the package to explain. Supports glob patterns like @org/* or *-lodash.

Options

• --top: Show only the top-level dependencies instead of the complete dependency tree.
• --depth <number>: Maximum depth of the dependency tree to display.

Examples

Check why a specific package is installed:

bun why react

[email protected]
  └─ [email protected] (requires ^18.0.0)

Check why all packages matching a pattern are installed:

bun why "@types/*"

@types/[email protected]
  └─ dev [email protected] (requires ^18.0.0)

@types/[email protected]
  └─ dev [email protected] (requires ^18.0.0)

Show only top-level dependencies:

bun why express --top

[email protected]
  └─ [email protected] (requires ^4.18.2)

Limit the dependency tree depth:

bun why express --depth 2

[email protected]
  └─ [email protected] (requires ^4.18.2)
     └─ [email protected] (requires ^1.20.1)
     └─ [email protected] (requires ^1.3.8)
        └─ (deeper dependencies hidden)

Understanding the Output

The output shows:

• The package name and version being queried
• The dependency chain that led to its installation
• The type of dependency (dev, peer, optional, or production)
• The version requirement specified in each package’s dependencies

For nested dependencies, the command shows the complete dependency tree by default, with indentation indicating the relationship hierarchy.