Amplitude JavaScript SDK (Legacy)

The `amplitude-js` library is the original JavaScript SDK for integrating web applications with Amplitude Analytics, enabling developers to track user events, user properties, and revenue data. Currently at version 8.21.10, this SDK primarily receives maintenance updates, with new feature development and a TypeScript-first approach now concentrated in the newer `@amplitude/analytics-browser` package. While `amplitude-js` continues to be functional for existing projects, it is no longer recommended for new browser-based instrumentations and has deprecated support for React Native since version 8.0.0, advising migration to `@amplitude/react-native` for cross-platform applications and `@amplitude/node` for server-side environments. Its release cadence has slowed significantly, focusing on bug fixes and dependency upgrades. It differentiates itself as the foundational Amplitude SDK before the introduction of more specialized and modern alternatives.