Merge pull request reactjs#153 from reactjs/sync-7b217c70

Sync with reactjs.org @ 7b217c7

Author: deblasis

content/community/conferences.md

@@ -22,6 +22,11 @@ May 25, 2019 in Yerevan, Armenia
 
 [Website](https://reactconf.am/) - [Twitter](https://twitter.com/ReactConfAM) - [Facebook](https://www.facebook.com/reactconf.am/) - [YouTube](https://www.youtube.com/c/JavaScriptConferenceArmenia) - [CFP](http://bit.ly/speakReact)
 
+### ReactNext 2019 {#react-next-2019}
+June 11, 2019. Tel Aviv, Israel
+
+[Website](https://react-next.com) - [Twitter](https://twitter.com/ReactNext) - [Videos](https://www.youtube.com/channel/UC3BT8hh3yTTYxbLQy_wbk2w)
+
 ### React Norway 2019 {#react-norway-2019}
 June 12, 2019. Larvik, Norway
 
@@ -57,6 +62,11 @@ 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
 

content/community/meetups.md

@@ -138,6 +138,7 @@ Do you have a local React.js meetup? Add it here! (Please keep the list alphabet
 * [Portland, OR - ReactJS](https://www.meetup.com/Portland-ReactJS/)
 * [Provo, UT - ReactJS](https://www.meetup.com/ReactJS-Utah/)
 * [Sacramento, CA - ReactJS](https://www.meetup.com/Sacramento-ReactJS-Meetup/)
+* [San Francisco - Real World React](https://www.meetup.com/Real-World-React)
 * [San Francisco - ReactJS](https://www.meetup.com/ReactJS-San-Francisco/)
 * [San Francisco, CA - React Native](https://www.meetup.com/React-Native-San-Francisco/)
 * [San Ramon, CA - TriValley Coders](https://www.meetup.com/trivalleycoders/)

content/docs/hooks-faq.md

@@ -844,9 +844,9 @@ Traditionally, performance concerns around inline functions in React have been r
     }, [a, b]);
     ```
 
-* The [`useMemo` Hook](/docs/hooks-faq.html#how-to-memoize-calculations) makes it easier to control when individual children update, reducing the need for pure components.
+* The [`useMemo`](/docs/hooks-faq.html#how-to-memoize-calculations) Hook makes it easier to control when individual children update, reducing the need for pure components.
 
-* Finally, the `useReducer` Hook reduces the need to pass callbacks deeply, as explained below.
+* Finally, the [`useReducer`](/docs/hooks-reference.html#usereducer) Hook reduces the need to pass callbacks deeply, as explained below.
 
 ### How to avoid passing callbacks down? {#how-to-avoid-passing-callbacks-down}
 

content/docs/hooks-intro.md

@@ -81,7 +81,7 @@ We'll discuss this more in [Using the Effect Hook](/docs/hooks-effect.html#tip-u
 
 In addition to making code reuse and code organization more difficult, we've found that classes can be a large barrier to learning React. You have to understand how `this` works in JavaScript, which is very different from how it works in most languages. You have to remember to bind the event handlers. Without unstable [syntax proposals](https://babeljs.io/docs/en/babel-plugin-transform-class-properties/), the code is very verbose. People can understand props, state, and top-down data flow perfectly well but still struggle with classes. The distinction between function and class components in React and when to use each one leads to disagreements even between experienced React developers.
 
-Additionally, React has been out for about five years, and we want to make sure it stays relevant in the next five years. As [Svelte](https://svelte.technology/), [Angular](https://angular.io/), [Glimmer](https://glimmerjs.com/), and others show, [ahead-of-time compilation](https://en.wikipedia.org/wiki/Ahead-of-time_compilation) of components has a lot of future potential. Especially if it's not limited to templates. Recently, we've been experimenting with [component folding](https://github.com/facebook/react/issues/7323) using [Prepack](https://prepack.io/), and we've seen promising early results. However, we found that class components can encourage unintentional patterns that make these optimizations fall back to a slower path. Classes present issues for today's tools, too. For example, classes don't minify very well, and they make hot reloading flaky and unreliable. We want to present an API that makes it more likely for code to stay on the optimizable path.
+Additionally, React has been out for about five years, and we want to make sure it stays relevant in the next five years. As [Svelte](https://svelte.dev/), [Angular](https://angular.io/), [Glimmer](https://glimmerjs.com/), and others show, [ahead-of-time compilation](https://en.wikipedia.org/wiki/Ahead-of-time_compilation) of components has a lot of future potential. Especially if it's not limited to templates. Recently, we've been experimenting with [component folding](https://github.com/facebook/react/issues/7323) using [Prepack](https://prepack.io/), and we've seen promising early results. However, we found that class components can encourage unintentional patterns that make these optimizations fall back to a slower path. Classes present issues for today's tools, too. For example, classes don't minify very well, and they make hot reloading flaky and unreliable. We want to present an API that makes it more likely for code to stay on the optimizable path.
 
 To solve these problems, **Hooks let you use more of React's features without classes.** Conceptually, React components have always been closer to functions. Hooks embrace functions, but without sacrificing the practical spirit of React. Hooks provide access to imperative escape hatches and don't require you to learn complex functional or reactive programming techniques.
 

content/docs/optimizing-performance.md

@@ -153,7 +153,7 @@ new webpack.DefinePlugin({
 new webpack.optimize.UglifyJsPlugin()
 ```
 
-You can learn more about this in [webpack documentation](https://webpack.js.org/guides/production-build/).
+You can learn more about this in [webpack documentation](https://webpack.js.org/guides/production/).
 
 Remember that you only need to do this for production builds. You shouldn't apply `UglifyJsPlugin` or `DefinePlugin` with `'production'` value in development because they will hide useful React warnings, and make the builds much slower.
 

content/docs/reference-javascript-environment-requirements.md

@@ -11,8 +11,8 @@ React 16 dipende dai tipi di collezione [Map](https://developer.mozilla.org/it/d
 Un ambiente con polyfill per React 16 utilizzando core-js per supportare browser più vecchi dovrebbe essere così:
 
 ```js
-import 'core-js/es6/map';
-import 'core-js/es6/set';
+import 'core-js/es/map';
+import 'core-js/es/set';
 
 import React from 'react';
 import ReactDOM from 'react-dom';

content/tutorial/tutorial.md

@@ -523,7 +523,7 @@ Nota come in `handleClick`, chiamiamo `.slice()` per creare una copia dell'array
 
 ### Perchè l'Immutabilità è Importante {#why-immutability-is-important}
 
-Nel precedente esempio di codice, abbiamo suggerito di usare l'operatore `.slice()` per creare una copia dell'array `squares` per modificarlo invece di modificare l'array esistente direttamente. Cerchiamo di capire cosa è l'immutabilità e perchè si tratta di un concetto importante da imparare.
+Nel precedente esempio di codice, abbiamo suggerito l'uso dell'operatore `.slice()` per creare una copia dell'array `squares` prima di modificarlo al posto della modifica diretta dell'array. Cerchiamo di capire cosa è l'immutabilità e perchè si tratta di un concetto importante da imparare.
 
 In generale, ci sono due approcci per modificare i dati. Il primo appoccio è quello di *mutarli* direttamente, cambiandone i valori. Il secondo approccio è quello di sostituire i dati con una nuova copia che ha i cambiamenti desiderati.