JS Recorder

The JS Recorder provides a lightweight, client-side instrumentation capability to capture events and function calls as your application runs. It is designed for frontend developers, testers, and reliability engineers who need deterministic traces to diagnose performance regressions and functional issues. The tool operates entirely in the browser, collecting timestamped records without requiring server-side changes. It exports data in a structured format suitable for offline analysis or ingestion by dashboards. The core concept is instrumentation through non-breaking wrappers around selected functions or event listeners and an optional sampling mode to minimize overhead. Each captured event includes type, timestamp, duration, and identifiers, enabling sequence reconstruction and latency calculations. The system supports optional stack traces, event filters, and call depth limits to keep traces focused and readable. Users can define which events to record (e.g., click handlers, fetch calls, custom events), set sampling rates, and specify a maximum number of records. After a session, the produced data can be downloaded as JSON or piped into a data pipeline, analytics platform, or CI/test suite for automated checks. The value of this tool lies in rapid, repeatable instrumentation without large setup costs, making it suitable for developers, QA teams, and performance engineers who need actionable traces without slowing down the application. It differentiates itself by providing deterministic timing, compact exports, and a straightforward workflow that integrates with existing debugging and profiling tasks.