CoreBoost v3.2.0

✨ New Feature - WordPress Core Script Defer

Critical Request Chain Optimization

• New "Defer WordPress Core Scripts" setting to break render-blocking chains from WordPress core JavaScript packages
• Targets wp-hooks, wp-i18n, and wp-dom-ready scripts that cause critical request chain latency in PageSpeed Insights
• Reduces Maximum Critical Path Latency by deferring these scripts while preserving execution order

How It Works

• Adds defer attribute to WordPress dist scripts, enabling parallel download during HTML parsing
• Scripts execute in document order after HTML parsing completes
• Includes preload hints (<link rel="preload">) for faster parallel downloads when enabled
• Frontend-only optimization — admin pages are never affected

Settings

• Location: Scripts tab → Script Exclusion Patterns section
• Default: Disabled (opt-in after testing)
• Requires: "Enable Script Defer" must also be enabled

Files Modified

• includes/class-coreboost.php - Added enable_wp_core_defer default option
• includes/admin/class-script-settings.php - Added setting field, callback, and sanitization
• includes/admin/class-settings-sanitizer.php - Added form context detection and field type mapping
• includes/public/class-script-optimizer.php - Added defer logic and preload hints for WP core scripts

Unit Tests

• Added tests/integration/ScriptOptimizerTest.php with 8 tests covering:
  • WP core scripts not deferred when disabled (default behavior)
  • WP core scripts deferred when enabled
  • Non-WP-core scripts unaffected
  • No duplicate defer attributes
  • No defer on scripts with async attribute
  • All three WP core handles recognized
  • Master enable_script_defer switch respected

Impact

Sites with Block Editor or Gutenberg-dependent plugins can reduce critical request chain latency significantly. Test thoroughly before enabling on production sites with complex Block Editor integrations.

---