Test Whether a Version Satisfies an npm Range

Testing npm Version Range Satisfaction

The core question in semver range matching is: does version X satisfy range Y? This is what npm install does every time it resolves dependencies.

How Range Satisfaction Works

A version satisfies a range if it falls within the bounds the range defines:

Version	Range	Satisfies?	Why
1.5.3	^1.2.0	✅	1.5.3 is >=1.2.0 and <2.0.0
2.0.0	^1.2.0	❌	2.0.0 is not <2.0.0
1.1.9	^1.2.0	❌	1.1.9 is not >=1.2.0
1.2.0	~1.2.0	✅	1.2.0 is >=1.2.0 and <1.3.0
1.3.0	~1.2.0	❌	1.3.0 is not <1.3.0

Step-by-Step Range Testing

To test a range manually:

1. Expand the range to its comparator form
   • ^1.2.0 → >=1.2.0 <2.0.0
   • ~1.2.0 → >=1.2.0 <1.3.0
   • 1.2.x → >=1.2.0 <1.3.0
2. Compare the version against each bound
3. All bounds must be satisfied (AND logic within a comparator set)
4. For OR ranges, at least one set must be satisfied

Pre-release Gotcha

npm has a special rule: a pre-release version only matches a range if the range includes a pre-release on the same MAJOR.MINOR.PATCH.

Version	Range	Satisfies?	Why
1.2.3-alpha.1	>=1.2.3-alpha.0	✅	Same base, higher pre-release
1.2.4-alpha.1	>=1.2.3	❌	Different base, pre-release excluded
1.2.3	>=1.2.3	✅	Release version, no restriction

Batch Testing

When evaluating multiple versions against a range (e.g., "which of these 50 versions match ^2.0.0?"), use the Batch Check tab to paste a list and see results highlighted instantly.

Common Testing Scenarios

• "Will this update break me?" — Test the new version against your range
• "Which versions can I install?" — Batch check against a list of published versions
• "Is my range too broad?" — Test edge cases like 0.x or pre-release versions