$ show thoughtbot/props_template
PropsTemplate is a Ruby gem that provides a high-performance DSL for building JSON responses in Rails applications. It bypasses the typical hash-building-then-serializing approach used by libraries like JBuilder by using Oj's StringWriter directly, resulting in significantly better performance. The library supports advanced features including Russian-doll caching, layouts, partial rendering, deferment (lazy loading), fragment tracking for SuperglueJS integration, and template digging/searching capabilities. The architecture is well-structured with clear separation between core JSON building logic, extension modules (cache, deferment, fragments, partials), and Rails integration components.
The LLM identified 3 files worth highlighting for reuse:
Implements the core JSON building functionality using Oj::StringWriter directly to avoid intermediate hash allocations. This is the key performance innovation that makes PropsTemplate faster than alternatives like JBuilder. The component manages scope tracking to properly handle nested objects and arrays, and is self-contained with minimal dependencies (only oj and active_support).
Implements Russian-doll caching specifically optimized for JSON templates by caching raw JSON strings and using Oj's push_json to insert them directly, avoiding the usual marshaling/unmarshaling overhead. The component handles cache key normalization, multi-fetch for arrays, and integrates cleanly with Rails caching mechanisms. It demonstrates non-obvious skill in optimizing caching for JSON serialization scenarios.
Provides the ability to search/dig into JSON templates to extract specific nodes without building the full JSON tree. Handles complex cases including arrays with custom member access, partials, caching, and deferment. The component efficiently walks the template structure while maintaining state, demonstrating non-obvious skill in tree traversal algorithms and context management for selective rendering.