---
title: "ReactJS.NET 1.3 - Faster server-side rendering and Flow"
layout: post
author: Daniel Lo Nigro
---

Hot on the heels of ReactJS.NET 1.2, I'm happy to announce the release of ReactJS.NET 1.3! This release significantly improves the performance of server-side rendering by pooling and reusing JavaScript engines rather than creating a new one on every request. Pooling of JavaScript engines is turned on by default but it can be disabled in your site's configuration (usually `ReactConfig.cs`) to revert back to the classic behaviour. This is still experimental, so please let me know if it works well for you!

This release also adds support for stripping out [Flow](http://flowtype.org/) type annotations from your code. Flow is a new open-source static type checker for JavaScript, recently released by Facebook. It adds static typing to JavaScript to improve developer productivity and code quality. You can learn more about Flow in [its release announcement](https://code.facebook.com/posts/1505962329687926/flow-a-new-static-type-checker-for-javascript/). Support for Flow is disabled by default but can be enabled in your site's configuration.

Other changes:

 * [Harmony (ES6)](/guides/es6.html) transformations are enabled by default. They can be disabled in your site's configuration.
 * The Cassette integration now transforms all files in the bundle, not just `*.jsx` files. ([#52](https://github.com/reactjs/React.NET/issues/52))

Have fun, and as always, please feel free to send feedback or bug reports
[on GitHub](https://github.com/reactjs/React.NET).

— Daniel
