Project

jQuery to Custom Library Migration

Replaced jQuery with a lightweight 6KB custom library, achieving 5x bundle size reduction and significant execution speed improvements.

JavaScriptjQueryPerformanceBundle Optimization

Overview

Led the initiative to replace jQuery across Bluecore's web application with a lightweight custom library. The migration reduced bundle size from 30KB to 6KB (5x reduction) and significantly improved execution speed without any loss of functionality.

Approach

  • Analyzed jQuery usage patterns across the entire codebase
  • Identified the most commonly used APIs and their dependencies
  • Built a minimal, tree-shakeable replacement using modern browser APIs
  • Implemented incremental migration strategy to avoid breaking changes

Results

  • Bundle size: 30KB → 6KB (80% reduction)
  • Execution speed: 3x faster DOM operations
  • Zero functionality loss across all supported browsers
  • All existing tests passed without modification

Technical Highlights

  • Leveraged modern DOM APIs (querySelector, classList, closest, etc.)
  • Implemented only the most-used jQuery patterns (DOM traversal, event delegation, AJAX)
  • Built with ES modules for tree-shaking compatibility
  • Maintained the same API surface for drop-in replacement