Chart.js JavaScript Charting

Chart.js is a free and open-source JavaScript charting library that provides simple yet flexible charts for web applications. Originally created by Nick Downie in 2013 (version 1), Chart.js was completely rewritten by Evert Timberg for version 2 (2016) with a new architecture, and has become one of the most popular charting libraries. Chart.js is used by over 50,000 websites. Key features: chart types: 8 built-in chart types including line, bar, horizontal bar, pie, doughnut, radar, polar area, and bubble charts. Each chart type has configurable options for appearance and behavior. Simple API: a chart is created by instantiating new Chart(canvas, config) where config specifies the type, data, and options. The data structure is straightforward (labels array and datasets with data, colors, labels). Responsiveness: charts automatically resize to their container. The maintainAspectRatio option controls aspect ratio. High-DPI rendering on retina displays. Animations: built-in smooth animations for data changes, transitions, and initial rendering. Configurable duration, easing, and per-property animation. Interactivity: hover effects, tooltips with customizable content and styling, clickable legend, and point/segment selection. Plugins: extensible plugin system. Official plugins for data labels, annotation, zoom, and crosshair. Community plugins for additional functionality. Scales: linear, logarithmic, category, time, and radial linear scales. Stacking: stack datasets in bar charts for cumulative displays. Mixed chart types: combine multiple chart types (e.g., bar + line) in a single chart. TypeScript support: version 3+ is written in TypeScript. Framework adapters: React, Vue, Angular wrappers. JavaScript/TypeScript. MIT.