Raven.js is the (legacy) browser JavaScript SDK for Sentry. If you are starting from scratch we advise you to use `@sentry/browser` found here. It automatically reports uncaught JavaScript exceptions triggered from a browser environment, and provides a rich API for reporting your own errors.
Sentry provides open source error tracking for development teams that shows every crash in the user stack as it happens, with the details needed to prioritize, identify, reproduce, and fix each issue.