Cal-Heatmap is a JavaScript charting library for creating time-series calendar heatmaps.
The library addresses the need to visualize temporal patterns and activity levels across calendar dates in a compact, scannable format. It uses a grid-based calendar view where each cell represents a time period and color intensity indicates the magnitude of the measured value, making it easy to spot trends, peaks, and gaps in time-series data at a glance.
The tool suits projects that need to display activity metrics, contributions, or other time-indexed measurements where patterns matter more than precise values. Common use cases include activity dashboards, contribution tracking, and temporal analytics. It integrates with D3.js for rendering and customization, so adopters should be comfortable with JavaScript and have some familiarity with D3 concepts if they need to extend the default behavior.
The project shows active maintenance with regular updates and responsive engagement with user issues and feature requests. Development activity demonstrates consistent attention to bug fixes and incremental improvements. The codebase is written in TypeScript, providing type safety for contributors and users who integrate it into typed projects.
