Merge branch 'master' into testing-recipes

Author: jakubdrozdek

CODE_OF_CONDUCT.md

@@ -1,5 +1,76 @@
 # Code of Conduct
 
-Facebook has adopted a Code of Conduct that we expect project participants to adhere to.
-Please read the [full text](https://code.fb.com/codeofconduct/)
-so that you can understand what actions will and will not be tolerated.
+## Our Pledge
+
+In the interest of fostering an open and welcoming environment, we as
+contributors and maintainers pledge to make participation in our project and
+our community a harassment-free experience for everyone, regardless of age, body
+size, disability, ethnicity, sex characteristics, gender identity and expression,
+level of experience, education, socio-economic status, nationality, personal
+appearance, race, religion, or sexual identity and orientation.
+
+## Our Standards
+
+Examples of behavior that contributes to creating a positive environment
+include:
+
+* Using welcoming and inclusive language
+* Being respectful of differing viewpoints and experiences
+* Gracefully accepting constructive criticism
+* Focusing on what is best for the community
+* Showing empathy towards other community members
+
+Examples of unacceptable behavior by participants include:
+
+* The use of sexualized language or imagery and unwelcome sexual attention or
+  advances
+* Trolling, insulting/derogatory comments, and personal or political attacks
+* Public or private harassment
+* Publishing others' private information, such as a physical or electronic
+  address, without explicit permission
+* Other conduct which could reasonably be considered inappropriate in a
+  professional setting
+
+## Our Responsibilities
+
+Project maintainers are responsible for clarifying the standards of acceptable
+behavior and are expected to take appropriate and fair corrective action in
+response to any instances of unacceptable behavior.
+
+Project maintainers have the right and responsibility to remove, edit, or
+reject comments, commits, code, wiki edits, issues, and other contributions
+that are not aligned to this Code of Conduct, or to ban temporarily or
+permanently any contributor for other behaviors that they deem inappropriate,
+threatening, offensive, or harmful.
+
+## Scope
+
+This Code of Conduct applies within all project spaces, and it also applies when
+an individual is representing the project or its community in public spaces.
+Examples of representing a project or community include using an official
+project e-mail address, posting via an official social media account, or acting
+as an appointed representative at an online or offline event. Representation of
+a project may be further defined and clarified by project maintainers.
+
+## Enforcement
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be
+reported by contacting the project team at <opensource-conduct@fb.com>. All
+complaints will be reviewed and investigated and will result in a response that
+is deemed necessary and appropriate to the circumstances. The project team is
+obligated to maintain confidentiality with regard to the reporter of an incident.
+Further details of specific enforcement policies may be posted separately.
+
+Project maintainers who do not follow or enforce the Code of Conduct in good
+faith may face temporary or permanent repercussions as determined by other
+members of the project's leadership.
+
+## Attribution
+
+This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4,
+available at https://www.contributor-covenant.org/version/1/4/code-of-conduct.html
+
+[homepage]: https://www.contributor-covenant.org
+
+For answers to common questions about this code of conduct, see
+https://www.contributor-covenant.org/faq

content/blog/2017-07-26-error-handling-in-react-16.md

@@ -111,4 +111,4 @@ Error boundaries preserve the declarative nature of React, and behave as you wou
 
 React 15 included a very limited support for error boundaries under a different method name: `unstable_handleError`. This method no longer works, and you will need to change it to `componentDidCatch` in your code starting from the first 16 beta release.
 
-For this change, we’ve provided [a codemod](https://github.com/reactjs/react-codemod#error-boundaries) to automatically migrate your code.
+For this change, we’ve provided a [codemod](https://github.com/reactjs/react-codemod#error-boundaries) to automatically migrate your code.

content/community/articles.md

@@ -14,3 +14,4 @@ permalink: community/articles.html
 - [Simple React Development in 2017](https://hackernoon.com/simple-react-development-in-2017-113bd563691f) - Joshua Comeau's guide to showcase how easy it can be to start modern React development.
 - [Visual Guide to State in React](https://daveceddia.com/visual-guide-to-state-in-react/) - Dave Ceddia's visual guide to React state.
 - [The Hands-On Guide to Learning React Hooks](https://www.telerik.com/kendo-react-ui/react-hooks-guide/) - Eric Bishard's step-by-step guide to learning React Hooks.
+- [How to Use the React Profiler Component to Measure Render Performance](https://medium.com/@adamhenson/how-to-use-the-react-profiler-component-to-measure-performance-improvements-from-hooks-d43b7092d7a8) - Adam Henson's article exemplifying a use case for `<React.Profiler />`.

content/community/conferences.md

@@ -12,36 +12,6 @@ Do you know of a local React.js conference? Add it here! (Please keep the list c
 
 ## Upcoming Conferences {#upcoming-conferences}
 
-### React Conf Iran 2019 {#react-conf-iran-2019}
-August 29, 2019. Tehran, Iran.
-
-[Website](https://reactconf.ir/) - [Twitter](https://twitter.com/reactconf_ir) - [Instagram](https://www.instagram.com/reactconf/)
-
-### React Rally 2019 {#react-rally-2019}
-August 22-23, 2019. Salt Lake City, USA.
-
-[Website](https://www.reactrally.com/) - [Twitter](https://twitter.com/ReactRally) - [Instagram](https://www.instagram.com/reactrally/)
-
-### ComponentsConf 2019 {#componentsconf-2019}
-September 6, 2019 in Melbourne, Australia
-
-[Website](https://www.componentsconf.com.au/) - [Twitter](https://twitter.com/componentsconf)
-
-### React Native EU 2019 {#react-native-eu-2019}
-September 5-6 in Wrocław, Poland
-
-[Website](https://react-native.eu) - [Twitter](https://twitter.com/react_native_eu) - [Facebook](https://www.facebook.com/reactnativeeu)
-
-### React New York 2019 {#react-new-york-2019}
-September 13th, 2019. New York, USA
-
-[Website](https://reactnewyork.com/) - [Twitter](https://twitter.com/reactnewyork)
-
-### React Live 2019 {#react-live-2019}
-September 13th, 2019. Amsterdam, The Netherlands
-
-[Website](https://www.reactlive.nl/) - [Twitter](https://twitter.com/reactlivenl)
-
 ### React Boston 2019 {#react-boston-2019}
 September 21-22, 2019 in Boston, Massachusetts USA
 
@@ -67,6 +37,11 @@ October 25, 2019 in London, UK
 
 [Website](https://reactadvanced.com) - [Twitter](http://twitter.com/reactadvanced) - [Facebook](https://www.facebook.com/ReactAdvanced) - [Videos](https://youtube.com/c/ReactConferences)
 
+### React Conf Brasil 2019 {#react-conf-2019}
+October 19, 2019 in São Paulo, BR
+
+[Website](https://reactconf.com.br/) - [Twitter](https://twitter.com/reactconfbr) - [Facebook](https://www.facebook.com/ReactAdvanced) - [Slack](https://react.now.sh/)
+
 ### React Day Berlin 2019 {#react-day-berlin-2019}
 December 6, 2019 in Berlin, Germany
 
@@ -92,9 +67,44 @@ June 15, 2020. Tel Aviv, Israel.
 
 [Website](https://react-next.com/) - [Twitter](https://twitter.com/reactnext) - [Facebook](https://www.facebook.com/ReactNext2016/) 
 
+### React Week NY 2020 {#react-week-NY-2020}
+July 17, 2020. New York City, USA.
+
+[Website](https://reactweek.nyc/) - [Twitter](https://twitter.com/reactweek) - [Facebook](https://www.facebook.com/reactweek) 
+
 
 ## Past Conferences {#past-conferences}
 
+### React Rally 2019 {#react-rally-2019}
+August 22-23, 2019. Salt Lake City, USA.
+
+[Website](https://www.reactrally.com/) - [Twitter](https://twitter.com/ReactRally) - [Instagram](https://www.instagram.com/reactrally/)
+
+### ComponentsConf 2019 {#componentsconf-2019}
+September 6, 2019 in Melbourne, Australia
+
+[Website](https://www.componentsconf.com.au/) - [Twitter](https://twitter.com/componentsconf)
+
+### React Native EU 2019 {#react-native-eu-2019}
+September 5-6 in Wrocław, Poland
+
+[Website](https://react-native.eu) - [Twitter](https://twitter.com/react_native_eu) - [Facebook](https://www.facebook.com/reactnativeeu)
+
+### React New York 2019 {#react-new-york-2019}
+September 13th, 2019. New York, USA
+
+[Website](https://reactnewyork.com/) - [Twitter](https://twitter.com/reactnewyork)
+
+### React Live 2019 {#react-live-2019}
+September 13th, 2019. Amsterdam, The Netherlands
+
+[Website](https://www.reactlive.nl/) - [Twitter](https://twitter.com/reactlivenl)
+
+### React Conf Iran 2019 {#react-conf-iran-2019}	
+August 29, 2019. Tehran, Iran.	
+
+[Website](https://reactconf.ir/) - [Videos](https://www.youtube.com/playlist?list=PL-VNqZFI5Nf-Nsj0rD3CWXGPkH-DI_0VY) - [Highlights](https://github.com/ReactConf/react-conf-highlights)
+
 ### React.js Conf 2015 {#reactjs-conf-2015}
 January 28 & 29 in Facebook HQ, CA
 

content/community/examples.md

@@ -21,3 +21,5 @@ There are many example projects created by the React community. Feel free to add
 * **[Bitcoin Price Index](https://github.com/mrkjlchvz/bitcoin-price-index)** Simple bitcoin price index data from CoinDesk API.
 * **[Builder Book](https://github.com/builderbook/builderbook)** Open source web app to write and host documentation or sell books. Built with React, Material-UI, Next, Express, Mongoose, MongoDB.
 * **[GFonts Space](https://github.com/pankajladhar/GFontsSpace)** A space which allows user to play with Google fonts. Built with React, Redux and React-Router.
+* **[Course Learn Page](https://github.com/ulearnpro/ulearn)** Open Source LMS script in Laravel 5.8 and ReactJS 16.9
+* **[Speedy math](https://github.com/pankajladhar/speedy-math)** An application which allows kids to practice basic Mathematics i.e  Addition, Subtraction, Multiply, Comparison. It is a PWA (Progressive web app) with offline support and install as App features.

content/community/meetups.md

@@ -25,6 +25,7 @@ Do you have a local React.js meetup? Add it here! (Please keep the list alphabet
 * [Joinville](https://www.meetup.com/pt-BR/React-Joinville/)
 * [Rio de Janeiro](https://www.meetup.com/pt-BR/React-Rio-de-Janeiro/)
 * [São Paulo](https://www.meetup.com/pt-BR/ReactJS-SP/)
+* [Vila Velha](https://www.meetup.com/pt-BR/React-ES/)
 
 ## Bolivia {#bolivia}
 * [Bolivia](https://www.meetup.com/ReactBolivia/)
@@ -58,7 +59,7 @@ Do you have a local React.js meetup? Add it here! (Please keep the list alphabet
 * [Karlsruhe](https://www.meetup.com/react_ka/)
 * [Kiel](https://www.meetup.com/Kiel-React-Native-Meetup/)
 * [Munich](https://www.meetup.com/ReactJS-Meetup-Munich/)
-* [React Berlin](https://www.meetup.com/React-Berlin/)
+* [React Berlin](https://www.meetup.com/React-Open-Source/)
 * [React.JS Girls Berlin](https://www.meetup.com/ReactJS-Girls-Berlin/)
 
 ## Greece {#greece}
@@ -144,6 +145,7 @@ Do you have a local React.js meetup? Add it here! (Please keep the list alphabet
 * [New York, NY - ReactJS](https://www.meetup.com/NYC-Javascript-React-Group/)
 * [New York, NY - React Ladies](https://www.meetup.com/React-Ladies/)
 * [New York, NY - React Native](https://www.meetup.com/React-Native-NYC/)
+* [New York, NY - useReactNYC](https://www.meetup.com/useReactNYC/)
 * [Palo Alto, CA - React Native](https://www.meetup.com/React-Native-Silicon-Valley/)
 * [Philadelphia, PA - ReactJS](https://www.meetup.com/RQ-React/)
 * [Phoenix, AZ - ReactJS](https://www.meetup.com/ReactJS-Phoenix/)

content/community/support.md

@@ -12,6 +12,8 @@ React has a community of millions of developers.
 
 On this page we've listed some React-related communities that you can be a part of; see the other pages in this section for additional online and in-person learning materials.
 
+Before participating in React's communities, [please read our Code of Conduct](https://github.com/facebook/react/blob/master/CODE_OF_CONDUCT.md). We have adopted the [Contributor Covenant](https://www.contributor-covenant.org/) and we expect that all community members adhere to the guidelines within.
+
 ## Stack Overflow {#stack-overflow}
 
 Stack Overflow is a popular forum to ask code-level questions or if you're stuck with a specific error. Read through the [existing questions](https://stackoverflow.com/questions/tagged/reactjs) tagged with **reactjs** or [ask your own](https://stackoverflow.com/questions/ask?tags=reactjs)!
@@ -24,7 +26,7 @@ Each community consists of many thousands of React users.
 
 * [DEV's React community](https://dev.to/t/react)
 * [Hashnode's React community](https://hashnode.com/n/reactjs)
-* [Reactiflux online chat](https://discord.gg/0ZcbPKXt5bZjGY5n)
+* [Reactiflux online chat](https://discord.gg/reactiflux)
 * [Reddit's React community](https://www.reddit.com/r/reactjs/)
 * [Spectrum's React community](https://spectrum.chat/react)
 

content/community/tools-debugging.md

@@ -5,4 +5,4 @@ layout: community
 permalink: community/debugging-tools.html
 ---
 
-  * **[React Developer Tools](https://github.com/facebook/react-devtools):** an extension available for [Chrome](https://chrome.google.com/webstore/detail/react-developer-tools/fmkadmapgofadopljbjfkapdkoienihi), [Firefox](https://addons.mozilla.org/firefox/addon/react-devtools/), and as a [standalone app](https://github.com/facebook/react-devtools/tree/master/packages/react-devtools) that allows you to inspect the React component hierarchy in the Chrome Developer Tools.
+  * **[React Developer Tools](https://github.com/facebook/react-devtools):** an extension available for [Chrome](https://chrome.google.com/webstore/detail/react-developer-tools/fmkadmapgofadopljbjfkapdkoienihi), [Firefox](https://addons.mozilla.org/firefox/addon/react-devtools/), and as a [standalone app](https://github.com/facebook/react/tree/master/packages/react-devtools) that allows you to inspect the React component hierarchy in the Chrome Developer Tools.

content/community/tools-ui-components.md

@@ -60,6 +60,7 @@ permalink: community/ui-components.html
 * **[react-uwp](https://www.react-uwp.com)** A set of React Components that Implement Microsoft's UWP Design & Fluent Design..
 * **[react-validate-framework](https://github.com/MinJieLiu/react-validate-framework)**: A lightweight and extensible React validation component.
 * **[reactstrap](https://reactstrap.github.io/):** Simple Bootstrap 4 components built with [tether](http://tether.io/)
+* **[Reakit](https://reakit.io/):** Toolkit for building accessible rich web apps with React.
 * **[recharts](https://github.com/recharts/recharts)**: A composable charting library built on React components.
 * **[Selectivity](https://arendjr.github.io/selectivity/):** Modular and light-weight selection library.
 * **[Semantic-ui](https://react.semantic-ui.com/)**: The official Semantic-UI-React integration, Advanced components and declarative UI.
@@ -78,3 +79,4 @@ permalink: community/ui-components.html
 * **[jQWidgets React components](https://www.jqwidgets.com/react/)**: Enterprise Ready 70+ UI Components.
 * **[KendoReact](https://www.telerik.com/kendo-react-ui/)**: UI for React Developers.
 * **[Mobiscroll React UI Components](https://mobiscroll.com/react)** Mobile UI Controls for the Productive React Developer.
+* **[React UI Toolkit](https://react-ui-tools.com/)**: 115+ professionally maintainted UI components ranging from a robust grid to charts and more. Try for FREE and build React apps faster.

content/docs/accessibility.md

@@ -45,7 +45,7 @@ Semantyczny HTML jest podstawą dostępności aplikacji webowych. Wykorzystując
 
 - [Dokumentacja elementów HTML na MDN](https://developer.mozilla.org/en-US/docs/Web/HTML/Element)
 
-Czasem łamiemy zasady semantycznego HTMl, kiedy dodajemy dodatkowy element `div` do naszego kodu JSX, aby uruchomić aplikację. Dzieje się tak zwłaszcza kiedy pracujemy z listami (`<ol>`, `<ul>` czy `<dl>`) oraz tabelami `<table>`.
+Czasem łamiemy zasady semantycznego HTML, kiedy dodajemy dodatkowy element `div` do naszego kodu JSX, aby uruchomić aplikację. Dzieje się tak zwłaszcza kiedy pracujemy z listami (`<ol>`, `<ul>` czy `<dl>`) oraz tabelami `<table>`.
 W takim przypadkach powinniśmy korzystać z [fragmentów reactowych](/docs/fragments.html), które pozwalają na grupowanie elementów.
 
 Przykład:

content/docs/code-splitting.md

@@ -126,41 +126,21 @@ Funkcja `React.lazy` pozwala renderować dynamicznie importowane komponenty jak
 
 ```js
 import OtherComponent from './OtherComponent';
-
-function MyComponent() {
-  return (
-    <div>
-      <OtherComponent />
-    </div>
-  );
-}
 ```
 
 **Po:**
 
 ```js
 const OtherComponent = React.lazy(() => import('./OtherComponent'));
-
-function MyComponent() {
-  return (
-    <div>
-      <OtherComponent />
-    </div>
-  );
-}
 ```
 
-Powyższy kod automatycznie załaduje paczkę zawierającą `OtherComponent` podczas renderowania komponentu.
+Powyższy kod automatycznie załaduje paczkę zawierającą `OtherComponent` podczas pierwszego renderowania komponentu.
 
 `React.lazy` jako argument przyjmuje funkcję, która wywołuje dynamiczny `import()`.
 Musi ona zwrócić obiekt (`Promise`) (pol. *obietnicę*), która rozwiązuje się do modułu z eksportem domyślnym (`default`) zawierającym
 komponent reactowy.
 
-### Zawieszenie (ang. *Suspense*) {#suspense}
-
-Jeśli moduł zawierający `OtherComponent` nie zostanie załadowany przed renderowaniem komponentu
-`MyComponent`, musimy wyświetlić alternatywną zawartość, dopóki trwa ładowanie - na przykład 
-wskaźnik ładowania. Robimy to za pomocą komponentu `Suspense`.
+"Leniwy" komponent powinien zostać wyrenderowany wewnątrz `Suspense`, dzięki któremu na czas ładowania możemy wyświetlić komponent zastępczy (np. wskaźnik ładowania).
 
 ```js
 const OtherComponent = React.lazy(() => import('./OtherComponent'));

content/docs/codebase-overview.md

@@ -217,7 +217,7 @@ Its source code is located in [`packages/react-reconciler`](https://github.com/f
 
 ### Event System {#event-system}
 
-React implements a synthetic event system which is agnostic of the renderers and works both with React DOM and React Native. Its source code is located in [`packages/events`](https://github.com/facebook/react/tree/master/packages/react-events).
+React implements a synthetic event system which is agnostic of the renderers and works both with React DOM and React Native. Its source code is located in [`packages/react-events`](https://github.com/facebook/react/tree/master/packages/react-events).
 
 There is a [video with a deep code dive into it](https://www.youtube.com/watch?v=dRo_egw7tBc) (66 mins).
 

content/docs/context.md

@@ -15,6 +15,7 @@ In a typical React application, data is passed top-down (parent to child) via pr
   - [Context.Provider](#contextprovider)
   - [Class.contextType](#classcontexttype)
   - [Context.Consumer](#contextconsumer)
+  - [Context.displayName](#contextdisplayname)
 - [Examples](#examples)
   - [Dynamic Context](#dynamic-context)
   - [Updating Context from a Nested Component](#updating-context-from-a-nested-component)
@@ -196,6 +197,20 @@ Requires a [function as a child](/docs/render-props.html#using-props-other-than-
 > 
 > For more information about the 'function as a child' pattern, see [render props](/docs/render-props.html).
 
+### `Context.displayName` {#contextdisplayname}
+
+Context object accepts a `displayName` string property. React DevTools uses this string to determine what to display for the context.
+
+For example, the following component will appear as MyDisplayName in the DevTools:
+
+```js{2}
+const MyContext = React.createContext(/* some value */);
+MyContext.displayName = 'MyDisplayName';
+
+<MyContext.Provider> // "MyDisplayName.Provider" in DevTools
+<MyContext.Consumer> // "MyDisplayName.Consumer" in DevTools
+```
+
 ## Examples {#examples}
 
 ### Dynamic Context {#dynamic-context}