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Clarify v15.0.0 changelog note about JS component klasses #6496

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Clarify v15.0.0 changelog note about JS component klasses #6496

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2 changes: 1 addition & 1 deletion CHANGELOG.md
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Expand Up @@ -15,7 +15,7 @@
- **`data-reactid` is no longer on every node.** As a result of using `document.createElement`, we can prime the node cache as we create DOM nodes, allowing us to skip a potential lookup (which used the `data-reactid` attribute). Root nodes will have a `data-reactroot` attribute and server generated markup will still contain `data-reactid`. ([@spicyj](https://github.com/spicyj) in [#5205](https://github.com/facebook/react/pull/5205))
- **No more extra `<span>`s.** ReactDOM will now render plain text nodes interspersed with comment nodes that are used for demarcation. This gives us the same ability to update individual pieces of text, without creating extra nested nodes. If you were targeting these `<span>`s in your CSS, you will need to adjust accordingly. You can always render them explicitly in your components. ([@mwiencek](https://github.com/mwiencek) in [#5753](https://github.com/facebook/react/pull/5753))
- **Rendering `null` now uses comment nodes.** Previously `null` would render to `<noscript>` elements. We now use comment nodes. This may cause issues if making use of `:nth-child` CSS selectors. While we consider this rendering behavior an implementation detail of React, it's worth noting the potential problem. ([@spicyj](https://github.com/spicyj) in [#5451](https://github.com/facebook/react/pull/5451))
- **Functional components can now return `null`.** We added support for [defining stateless components as functions](/react/blog/2015/09/10/react-v0.14-rc1.html#stateless-function-components) in React 0.14. However, React 0.14 still allowed you to define a class component without extending `React.Component` or using `React.createClass()`, so [we couldn’t reliably tell if your component is a function or a class](https://github.com/facebook/react/issues/5355), and did not allow returning `null` from it. This issue is solved in React 15, and you can now return `null` from any component, whether it is a class or a function. ([@jimfb](https://github.com/jimfb) in [#5884](https://github.com/facebook/react/pull/5884))
- **Functional components can now return `null`.** We added support for [defining stateless components as functions](/react/blog/2015/09/10/react-v0.14-rc1.html#stateless-function-components) in React 0.14. However, React 0.14 still allowed you to define a component `class` without extending `React.Component` (e.g. `class Hello {}`), so [we couldn’t reliably differentiate between a stateless functional component and a `ReactClass`](https://github.com/facebook/react/issues/5355) and did not allow returning `null` from a stateless functional component. This issue is solved in React 15, and you can now return `null` when rendering any component, whether it is a `ReactClass` or stateless functional. ([@jimfb](https://github.com/jimfb) in [#5884](https://github.com/facebook/react/pull/5884))
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What about flipping this to be using pure functions as "stateless" components? I think it gets the idea across a little more clearly.

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I assume you're referring to changing "defining stateless components as functions".

I have no objections. To be clear, class components can also be "stateless" and therefore technically match the term "stateless components", but I don't think that makes your version incorrect.

- **Improved SVG support.** All SVG tags are now fully supported. (Uncommon SVG tags are not present on the `React.DOM` element helper, but JSX and `React.createElement` work on all tag names.) All SVG attributes that are implemented by the browsers should be supported too. If you find any attributes that we have missed, please [let us know in this issue](https://github.com/facebook/react/issues/1657). ([@zpao](https://github.com/zpao) in [#6243](https://github.com/facebook/react/pull/6243))

### Breaking changes
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