perf(setDefaultsOnInsert): avoid computing all modified paths when running setDefaultsOnInsert and update validators, only calculate if there are defaults to set

[vkarpov15]

Summary

Got another 50% speedup on #15672 by removing modifiedPaths() from setDefaultsOnInsert, and then similar results if runValidators is set by removing modifiedPaths() from update validators (which was very easy since it turns out runValidators doesn't even use modifiedPaths)

Examples

[Copilot]

Pull Request Overview

This PR optimizes performance for setDefaultsOnInsert and update validators by eliminating unnecessary modifiedPaths() computations. The change achieves a 50% speedup by only calculating modified paths when there are actual defaults to set.

Key changes:

• Added early return in getDefault() when defaultValue is null
• Removed modifiedPaths() calls from update validators since they weren't being used
• Refactored setDefaultsOnInsert to check path modifications inline instead of pre-computing all modified paths

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
lib/schemaType.js	Added null check for early return in getDefault() to avoid unnecessary computation
lib/helpers/updateValidators.js	Removed unused modifiedPaths import and all related computation
lib/helpers/setDefaultsOnInsert.js	Replaced pre-computed modified paths with inline path checking, optimized operator detection using charAt(0)

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