[nigrosimone]

largeArrayMechanism and largeArraySize are module-level variables that build overwrites when the options are given and never resets. After fastJson(schema, { largeArrayMechanism: 'json-stringify', largeArraySize: 3 }), every later fastJson(otherSchema) without those options serializes arrays of 3 or more items through JSON.stringify, which drops the item schema: a date formatted array comes out with full ISO strings.

The fix keeps both on the build context, with the defaults applied on every build.

The added test builds once with the options and once without, on the same schema, and checks the second one formats the dates: it fails on main and passes here.

[Tony133]

Closing as superseded by #899, which makes the large-array options local to each build() call instead of module-wide. The format: 'date' regression test from this PR fails on the commit right before #899 and passes on current main, so the fix is already in. Thanks for the contribution!