16.1.1 (November 13, 2017)

React

• Improve the warning about undefined component type. (@selbekk in #11505)

React DOM

• Support string values for the capture attribute. (@maxschmeling in #11424)

React DOM Server

• Don't freeze the ReactDOMServer public API. (@travi in #11531)
• Don't emit autoFocus={false} attribute on the server. (@gaearon in #11543)

React Reconciler

• Change the hydration API for better Flow typing. (@sebmarkbage in #11493)

16.1.0 (November 9, 2017)

Discontinuing Bower Releases

Starting with 16.1.0, we will no longer be publishing new releases on Bower. You can continue using Bower for old releases, or point your Bower configs to the React UMD builds hosted on unpkg that mirror npm releases and will continue to be updated.

All Packages

• Fix an accidental extra global variable in the UMD builds. (@gaearon in #10935)

React

• Add support for portals in React.Children utilities. (@MatteoVH in #11378)
• Warn when a class has a render method but doesn't extend a known base class. (@sw-yx in #11168)
• Improve the warning when accidentally returning an object from constructor. (@deanbrophy in #11395)

React DOM

• Allow on as a custom attribute for AMP. (@nuc in #11153)
• Fix onMouseEnter and onMouseLeave firing on wrong elements. (@gaearon in #11164)
• Fix null showing up in a warning instead of the component stack. (@gaearon in #10915)
• Fix IE11 crash in development mode. (@leidegre in #10921)
• Fix tabIndex not getting applied to SVG elements. (@gaearon in #11034)
• Fix SVG children not getting cleaned up on dangerouslySetInnerHTML in IE. (@OriR in #11108)
• Fix false positive text mismatch warning caused by newline normalization. (@gaearon in #11119)
• Fix form.reset() to respect defaultValue on uncontrolled <select>. (@aweary in #11057)
• Fix <textarea> placeholder not rendering on IE11. (@gaearon in #11177)
• Fix a crash rendering into shadow root. (@gaearon in #11037)
• Fix false positive warning about hydrating mixed case SVG tags. (@gaearon in #11174)
• Suppress the new unknown tag warning for <dialog> element. (@gaearon in #11035)
• Warn when defining a non-existent componentDidReceiveProps method. (@iamtommcc in #11479)
• Warn about function child no more than once. (@andreysaleba in #11120)
• Warn about nested updates no more than once. (@anushreesubramani in #11113)
• Deduplicate other warnings about updates. (@anushreesubramani in #11216)
• Include component stack into the warning about contentEditable and children. (@Ethan-Arrowood in #11208)
• Improve the warning about booleans passed to event handlers. (@NicBonetto in #11308)
• Improve the warning when a multiple select gets null value. (@Hendeca in #11141)
• Move link in the warning message to avoid redirect. (@marciovicente in #11400)
• Add a way to suppress the React DevTools installation prompt. (@gaearon in #11448)
• Remove unused code. (@gaearon in #10802, #10803)

React DOM Server

• Add a new suppressHydrationWarning attribute for intentional client/server text mismatches. (@sebmarkbage in #11126)
• Fix markup generation when components return strings. (@gaearon in #11109)
• Fix obscure error message when passing an invalid style value. (@iamdustan in #11173)
• Include the autoFocus attribute into SSR markup. (@gaearon in #11192)
• Include the component stack into more warnings. (@gaearon in #11284)

React Test Renderer and Test Utils

• Fix multiple setState() calls in componentWillMount() in shallow renderer. (@Hypnosphi in #11167)
• Fix shallow renderer to ignore shouldComponentUpdate() after forceUpdate(). (@d4rky-pl in #11239 and #11439)
• Handle forceUpdate() and React.PureComponent correctly. (@koba04 in #11440)
• Add back support for running in production mode. (@gaearon in #11112)
• Add a missing package.json dependency. (@gaearon in #11340)

React ART

• Add a missing package.json dependency. (@gaearon in #11341)
• Expose react-art/Circle, react-art/Rectangle, and react-art/Wedge. (@gaearon in #11343)

React Reconciler (Experimental)

• First release of the new experimental package for creating custom renderers. (@iamdustan in #10758)
• Add support for React DevTools. (@gaearon in #11463)

React Call Return (Experimental)

• First release of the new experimental package for parent-child communication. (@gaearon in #11364)

16.0.0 (September 26, 2017)

Learn more in the React 16.0 announcement post!

New JS Environment Requirements

• React 16 depends on the collection types Map and Set, as well as requestAnimationFrame. If you support older browsers and devices which may not yet provide these natively (e.g. <IE11), you may want to include a polyfill.

New Features

• Components can now return arrays and strings from render. (Docs coming soon!)
• Improved error handling with introduction of "error boundaries". Error boundaries are React components that catch JavaScript errors anywhere in their child component tree, log those errors, and display a fallback UI instead of the component tree that crashed.
• First-class support for declaratively rendering a subtree into another DOM node with ReactDOM.createPortal(). (Docs coming soon!)
• Streaming mode for server side rendering is enabled with ReactDOMServer.renderToNodeStream() and ReactDOMServer.renderToStaticNodeStream(). (@aickin in #10425, #10044, #10039, #10024, #9264, and others.)
• React DOM now allows passing non-standard attributes. (@nhunzaker in #10385, 10564, #10495 and others)

Breaking Changes

• There are several changes to the behavior of scheduling and lifecycle methods:
  • ReactDOM.render() and ReactDOM.unstable_renderIntoContainer() now return null if called from inside a lifecycle method.
    • To work around this, you can either use the new portal API or refs.
  • Minor changes to setState behavior:
    • Calling setState with null no longer triggers an update. This allows you to decide in an updater function if you want to re-render.
    • Calling setState directly in render always causes an update. This was not previously the case. Regardless, you should not be calling setState from render.
    • setState callback (second argument) now fires immediately after componentDidMount / componentDidUpdate instead of after all components have rendered.
  • When replacing <A /> with <B />, B.componentWillMount now always happens before A.componentWillUnmount. Previously, A.componentWillUnmount could fire first in some cases.
  • Previously, changing the ref to a component would always detach the ref before that component's render is called. Now, we change the ref later, when applying the changes to the DOM.
  • It is not safe to re-render into a container that was modified by something other than React. This worked previously in some cases but was never supported. We now emit a warning in this case. Instead you should clean up your component trees using ReactDOM.unmountComponentAtNode. See this example.
  • componentDidUpdate lifecycle no longer receives prevContext param. (@bvaughn in #8631)
  • Non-unique keys may now cause children to be duplicated and/or omitted. Using non-unique keys is not (and has never been) supported, but previously it was a hard error.
  • Shallow renderer no longer calls componentDidUpdate() because DOM refs are not available. This also makes it consistent with componentDidMount() (which does not get called in previous versions either).
  • Shallow renderer does not implement unstable_batchedUpdates() anymore.
  • ReactDOM.unstable_batchedUpdates now only takes one extra argument after the callback.
• The names and paths to the single-file browser builds have changed to emphasize the difference between development and production builds. For example:
  • react/dist/react.js → react/umd/react.development.js
  • react/dist/react.min.js → react/umd/react.production.min.js
  • react-dom/dist/react-dom.js → react-dom/umd/react-dom.development.js
  • react-dom/dist/react-dom.min.js → react-dom/umd/react-dom.production.min.js

• The server renderer has been completely rewritten, with some improvements:
  • Server rendering does not use markup validation anymore, and instead tries its best to attach to existing DOM, warning about inconsistencies. It also doesn't use comments for empty components and data-reactid attributes on each node anymore.
  • Hydrating a server rendered container now has an explicit API. Use ReactDOM.hydrate instead of ReactDOM.render if you're reviving server rendered HTML. Keep using ReactDOM.render if you're just doing client-side rendering.
• When "unknown" props are passed to DOM components, for valid values, React will now render them in the DOM. See this post for more details. (@nhunzaker in #10385, 10564, #10495 and others)
• Errors in the render and lifecycle methods now unmount the component tree by default. To prevent this, add error boundaries to the appropriate places in the UI.

Removed Deprecations

• There is no react-with-addons.js build anymore. All compatible addons are published separately on npm, and have single-file browser versions if you need them.
• The deprecations introduced in 15.x have been removed from the core package. React.createClass is now available as create-react-class, React.PropTypes as prop-types, React.DOM as react-dom-factories, react-addons-test-utils as react-dom/test-utils, and shallow renderer as react-test-renderer/shallow. See 15.5.0 and 15.6.0 blog posts for instructions on migrating code and automated codemods.