React v0.9
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I’m excited to announce that today we’re releasing React v0.9, which incorporates many bug fixes and several new features since the last release. This release contains almost four months of work, including over 800 commits from over 70 committers!
Thanks to everyone who tested the release candidate; we were able to find and fix an error in the event handling code, we upgraded envify to make running browserify on React faster, and we added support for five new attributes.
As always, the release is available for download from the CDN:
- React
Dev build with warnings: https://fb.me/react-0.9.0.js
Minified build for production: https://fb.me/react-0.9.0.min.js - React with Add-Ons
Dev build with warnings: https://fb.me/react-with-addons-0.9.0.js
Minified build for production: https://fb.me/react-with-addons-0.9.0.min.js - In-Browser JSX Transformer
https://fb.me/JSXTransformer-0.9.0.js
We’ve also published version 0.9.0 of the react and react-tools packages on npm and the react package on bower.
What’s New?
This version includes better support for normalizing event properties across all supported browsers so that you need to worry even less about cross-browser differences. We’ve also made many improvements to error messages and have refactored the core to never rethrow errors, so stack traces are more accurate and Chrome’s purple break-on-error stop sign now works properly.
We’ve also added to the add-ons build React.addons.TestUtils, a set of new utilities to help you write unit tests for React components. You can now simulate events on your components, and several helpers are provided to help make assertions about the rendered DOM tree.
We’ve also made several other improvements and a few breaking changes; the full changelog is provided below.
JSX Whitespace
In addition to the changes to React core listed below, we’ve made a small change to the way JSX interprets whitespace to make things more consistent. With this release, space between two components on the same line will be preserved, while a newline separating a text node from a tag will be eliminated in the output. Consider the code:
<div>
Monkeys:
{listOfMonkeys} {submitButton}
</div>In v0.8 and below, it was transformed to the following:
React.DOM.div(null,
" Monkeys: ",
listOfMonkeys, submitButton
)In v0.9, it will be transformed to this JS instead:
React.DOM.div(null,
"Monkeys:", listOfMonkeys, " ", submitButton)We believe this new behavior is more helpful and eliminates cases where unwanted whitespace was previously added.
In cases where you want to preserve the space adjacent to a newline, you can write {'Monkeys: '} or Monkeys:{' '} in your JSX source. We’ve included a script to do an automated codemod of your JSX source tree that preserves the old whitespace behavior by adding and removing spaces appropriately. You can install jsx_whitespace_transformer from npm and run it over your source tree to modify files in place. The transformed JSX files will preserve your code’s existing whitespace behavior.
Changelog
React Core
Breaking Changes
- The lifecycle methods
componentDidMountandcomponentDidUpdateno longer receive the root node as a parameter; usethis.getDOMNode()instead - Whenever a prop is equal to
undefined, the default value returned bygetDefaultPropswill now be used instead React.unmountAndReleaseReactRootNodewas previously deprecated and has now been removedReact.renderComponentToStringis now synchronous and returns the generated HTML string- Full-page rendering (that is, rendering the
<html>tag using React) is now supported only when starting with server-rendered markup - On mouse wheel events,
deltaYis no longer negated - When prop types validation fails, a warning is logged instead of an error thrown (with the production build of React, type checks are now skipped for performance)
- On
input,select, andtextareaelements,.getValue()is no longer supported; use.getDOMNode().valueinstead this.contexton components is now reserved for internal use by React
New Features
- React now never rethrows errors, so stack traces are more accurate and Chrome’s purple break-on-error stop sign now works properly
- Added support for SVG tags
defs,linearGradient,polygon,radialGradient,stop -
Added support for more attributes:
crossOriginfor CORS requestsdownloadandhrefLangfor<a>tagsmediaGroupandmutedfor<audio>and<video>tagsnoValidateandformNoValidatefor formspropertyfor Open Graph<meta>tagssandbox,seamless, andsrcDocfor<iframe>tagsscopefor screen readersspanfor<colgroup>tags
- Added support for defining
propTypesin mixins - Added
any,arrayOf,component,oneOfType,renderable,shapetoReact.PropTypes - Added support for
staticson component spec for static component methods - On all events,
.currentTargetis now properly set - On keyboard events,
.keyis now polyfilled in all browsers for special (non-printable) keys - On clipboard events,
.clipboardDatais now polyfilled in IE - On drag events,
.dataTransferis now present - Added support for
onMouseOverandonMouseOutin addition to the existingonMouseEnterandonMouseLeaveevents - Added support for
onLoadandonErroron<img>elements - Added support for
onReseton<form>elements - The
autoFocusattribute is now polyfilled consistently oninput,select, andtextarea
Bug Fixes
- React no longer adds an
__owner__property to each component’spropsobject; passed-in props are now never mutated - When nesting top-level components (e.g., calling
React.renderComponentwithincomponentDidMount), events now properly bubble to the parent component - Fixed a case where nesting top-level components would throw an error when updating
- Passing an invalid or misspelled propTypes type now throws an error
- On mouse enter/leave events,
.target,.relatedTarget, and.typeare now set properly - On composition events,
.datais now properly normalized in IE9 and IE10 - CSS property values no longer have
pxappended for the unitless propertiescolumnCount,flex,flexGrow,flexShrink,lineClamp,order,widows - Fixed a memory leak when unmounting children with a
componentWillUnmounthandler - Fixed a memory leak when
renderComponentToStringwould store event handlers - Fixed an error that could be thrown when removing form elements during a click handler
- Boolean attributes such as
disabledare rendered without a value (previouslydisabled="true", now simplydisabled) keyvalues containing.are now supported- Shortened
data-reactidvalues for performance - Components now always remount when the
keyproperty changes - Event handlers are attached to
documentonly when necessary, improving performance in some cases - Events no longer use
.returnValuein modern browsers, eliminating a warning in Chrome scrollLeftandscrollTopare no longer accessed on document.body, eliminating a warning in Chrome- General performance fixes, memory optimizations, improvements to warnings and error messages
React with Addons
React.addons.TestUtilswas added to help write unit testsReact.addons.TransitionGroupwas renamed toReact.addons.CSSTransitionGroupReact.addons.TransitionGroupwas added as a more general animation wrapperReact.addons.cloneWithPropswas added for cloning components and modifying their props- Bug fix for adding back nodes during an exit transition for CSSTransitionGroup
- Bug fix for changing
transitionLeavein CSSTransitionGroup - Performance optimizations for CSSTransitionGroup
- On checkbox
<input>elements,checkedLinkis now supported for two-way binding
JSX Compiler and react-tools Package
- Whitespace normalization has changed; now space between two tags on the same line will be preserved, while newlines between two tags will be removed
- The
react-toolsnpm package no longer includes the React core libraries; use thereactpackage instead. displayNameis now added in more cases, improving error messages and names in the React Dev Tools- Fixed an issue where an invalid token error was thrown after a JSX closing tag
JSXTransformernow uses source maps automatically in modern browsersJSXTransformererror messages now include the filename and problematic line contents when a file fails to parse