React: v0.5.0 Release

React

• Memory usage improvements - reduced allocations in core which will help with GC pauses
• Performance improvements - in addition to speeding things up, we made some tweaks to stay out of slow path code in V8 and Nitro.
• Standardized prop -> DOM attribute process. This previously resulting in additional type checking and overhead as well as confusing cases for users. Now we will always convert your value to a string before inserting it into the DOM.
• Support for Selection events.
• Support for Composition events.
• Support for additional DOM properties (charSet, content, form, httpEquiv, rowSpan, autoCapitalize).
• Support for additional SVG properties (rx, ry).
• Support for using getInitialState and getDefaultProps in mixins.
• Support mounting into iframes.
• Bug fixes for controlled form components.
• Bug fixes for SVG element creation.
• Added React.version.
• Added React.isValidClass - Used to determine if a value is a valid component constructor.
• Removed React.autoBind - This was deprecated in v0.4 and now properly removed.
• Renamed React.unmountAndReleaseReactRootNode to React.unmountComponentAtNode.
• Began laying down work for refined performance analysis.
• Better support for server-side rendering - react-page has helped improve the stability for server-side rendering.
• Made it possible to use React in environments enforcing a strict Content Security Policy. This also makes it possible to use React to build Chrome extensions.

React with Addons (New!)

• Introduced a separate build with several "addons" which we think can help improve the React experience. We plan to deprecate this in the long-term, instead shipping each as standalone pieces. Read more in the docs.

JSX

• No longer transform class to className as part of the transform! This is a breaking change - if you were using class, you must change this to className or your components will be visually broken.
• Added warnings to the in-browser transformer to make it clear it is not intended for production use.
• Improved compatibility for Windows
• Improved support for maintaining line numbers when transforming.