Jest

Snapshots Commands

Use snapshot testing to detect unexpected UI or data changes. Jest captures output and compares against stored snapshots, making it easy to catch regressions.

4 commands

Pro Tips

Use 'jest --updateSnapshot' or press 'u' in watch mode to update snapshots after intentional changes.

Prefer 'toMatchInlineSnapshot()' for small outputs — keeps expected values visible right in the test file.

Use snapshot serializers to remove volatile data like timestamps and IDs before snapshotting.

Common Mistakes

Don't blindly update snapshots. Review changes in 'jest --updateSnapshot' to ensure they're intentional.

Large snapshots are hard to review and easy to approve without reading. Keep snapshots focused and small.

Commands

Update snapshots

$ jest -u

Update all failing snapshots.

Update snapshots full

$ jest --updateSnapshot

Update all failing snapshots (full flag).

Clear cache

$ jest --clearCache

Delete Jest cache directory.

Disable cache

$ jest --no-cache

Run tests without cache.