Currently, ArrayUtils class has many responsibility, thus breaking it into specific usage will open more opportunities to enhance its features - also to properly benchmark edge cases of each functionality (e.g. caching validation and array merging strategies)

Responsibilities

1. Validation Strategies
   • hasStringKey
   • hasIntegerKey
   • hasNumericKeys
   • isList
   • isHashTable
   • isCachable (proposed/new feature)
2. Merging Strategies
   • Integer and String Keys
   • Integer and String With Preserved Numeric Keys
   • Recursive Merging
   • Merging with Null arrays
   • Replacing/Removing Keys
   • Prioritized Merging (proposed/new feature)
3. Filtering Strategies
   • Without key filtering
   • Key specific filtering
   • With and without key filtering
4. Iterator to Array Conversion Strategies
   • Simple Iterator
   • Recursive Iterator

Benchmarking

Benchmarking the merging and caching strategies is a MUST.

One way of validating performance issue is to benchmark, especially, configuration from Zend\ServiceManager, Zend\View, Zend\Router, etc.