Deno Land has officially released Deno 2.2, an updated version of the popular JavaScript and TypeScript runtime that brings significant enhancements. One of the most notable additions in this release is built-in OpenTelemetry support, enabling developers to monitor logs, metrics, and traces directly within Deno. This integration allows for automatic instrumentation of common APIs like console.log, Deno.serve, and fetch. For more customized observability, developers can leverage the OpenTelemetry API package via npm and connect to an OTLP endpoint. For those working in development or testing environments, Deno Land recommends using Grafana’s LGTM Docker image to capture telemetry data effectively.
Released on February 19, Deno 2.2 is easily accessible for existing users through a simple upgrade command, deno upgrade. New users can find installation instructions on the official Deno website. Alongside telemetry improvements, the release introduces a substantial upgrade to the built-in linter, deno lint. This upgrade includes a fresh plugin system and a set of 15 new linting rules tailored specifically for React and Preact developers. These rules cover a wide range of best practices and error prevention techniques, such as enforcing JSX boolean values, requiring button types, and prohibiting duplicate or unsafe JSX properties.
Performance optimizations are also a key focus in Deno 2.2. The runtime now clears module analysis data after a set timeout, reducing memory usage and improving efficiency. Windows users will notice a speed boost with the Deno.stat and node:fs.stat functions running up to 2.5 times faster. Additionally, improvements to Node.js module resolution have been made by minimizing costly conversions between URLs and file paths, further enhancing Deno’s compatibility and speed when working with Node.js modules.
The update also extends the functionality of the deno outdated tool by adding an interactive interface for managing dependency updates, making maintenance simpler for developers. Compatibility with Node.js and npm continues to improve with Deno 2.2, including support for .npmrc configuration files located both in the user’s home and project directories. Overall, this release strengthens Deno’s position as a versatile and efficient runtime for modern web development.