Merge pull request #175 from reactjs/sync-986381c5

Sync with reactjs.org @ 986381c

Author: deblasis

content/blog/2019-02-23-is-react-translated-yet.md

@@ -23,7 +23,7 @@ In the past, React community members have created unofficial translations for [C
 
 If you would like to help out on a current translation, check out the [Languages](/languages) page and click on the "Contribute" link for your language.
 
-Can't find your language? If you'd like to maintain your langauge's translation fork, follow the instructions in the [translation repo](https://github.com/reactjs/reactjs.org-translation#starting-a-new-translation)!
+Can't find your language? If you'd like to maintain your language's translation fork, follow the instructions in the [translation repo](https://github.com/reactjs/reactjs.org-translation#starting-a-new-translation)!
 
 ## Backstory {#backstory}
 

content/community/conferences.md

@@ -52,6 +52,11 @@ September 26-28, 2019 in Alicante, Spain
 
 [Website](http://reactalicante.es/) - [Twitter](https://twitter.com/reactalicante) - [Facebook](https://www.facebook.com/ReactAlicante)
 
+### React Conf 2019 {#react-conf-2019}
+October 24-25, 2019 in Henderson, Nevada USA
+
+[Website](https://conf.reactjs.org/) - [Twitter](https://twitter.com/reactjs)
+
 ### React Advanced 2019 {#react-advanced-2019}
 October 25, 2019 in London, UK
 
@@ -62,6 +67,16 @@ December 6, 2019 in Berlin, Germany
 
 [Website](https://reactday.berlin) - [Twitter](https://twitter.com/reactdayberlin) - [Facebook](https://www.facebook.com/reactdayberlin/) - [Videos](https://www.youtube.com/reactdayberlin)
 
+### ReactConf AU 2020 {#reactconfau}
+February 27 & 28, 2020 in Sydney, Australia
+
+[Website](https://reactconfau.com/) - [Twitter](https://twitter.com/reactconfau) - [Facebook](https://www.facebook.com/reactconfau) - [Instagram](https://www.instagram.com/reactconfau/)
+
+### Render-Atlanta 2020 {#render-atlanta-2020}
+May 4-6, 2020. Atlanta, GA, USA.
+
+[Website](https://renderatl.com)
+
 ## Past Conferences {#past-conferences}
 
 ### React.js Conf 2015 {#reactjs-conf-2015}
@@ -395,3 +410,4 @@ June 21, 2019 Chicago, Illinois USA
 July 11-12, 2019. Portland, OR, USA.
 
 [Website](https://infinite.red/ChainReactConf)
+

content/docs/hooks-faq.md

@@ -567,7 +567,7 @@ Depending on your use case, there are a few more options described below.
 
 Let's see why this matters.
 
-If you specify a [list of dependencies](/docs/hooks-reference.html#conditionally-firing-an-effect) as the last argument to `useEffect`, `useMemo`, `useCallback`, or `useImperativeHandle`, it must include all values used inside that participate in the React data flow. That includes props, state, and anything derived from them.  
+If you specify a [list of dependencies](/docs/hooks-reference.html#conditionally-firing-an-effect) as the last argument to `useEffect`, `useMemo`, `useCallback`, or `useImperativeHandle`, it must include all values used inside that participate in the React data flow. That includes props, state, and anything derived from them.
 
 It is **only** safe to omit a function from the dependency list if nothing in it (or the functions called by it) references props, state, or values derived from them. This example has a bug:
 
@@ -618,7 +618,7 @@ This also allows you to handle out-of-order responses with a local variable insi
       const json = await response.json();
       if (!ignore) setProduct(json);
     }
-    
+
     fetchProduct();
     return () => { ignore = true };
   }, [productId]);
@@ -677,7 +677,7 @@ function Counter() {
 
 The empty set of dependencies, `[]`, means that the effect will only run once when the component mounts, and not on every re-render. The problem is that inside the `setInterval` callback, the value of `count` does not change, because we've created a closure with the value of `count` set to `0` as it was when the effect callback ran. Every second, this callback then calls `setCount(0 + 1)`, so the count never goes above 1.
 
-Specifying `[count]` as a list of dependencies would fix the bug, but would cause the interval to be reset on every change. Effectively, each `setInterval` would get one chance to execute before being cleared (similar to a `setTimout`.) That may not be desirable. To fix this, we can use the [functional update form of `setState`](/docs/hooks-reference.html#functional-updates). It lets us specify *how* the state needs to change without referencing the *current* state:
+Specifying `[count]` as a list of dependencies would fix the bug, but would cause the interval to be reset on every change. Effectively, each `setInterval` would get one chance to execute before being cleared (similar to a `setTimeout`.) That may not be desirable. To fix this, we can use the [functional update form of `setState`](/docs/hooks-reference.html#functional-updates). It lets us specify *how* the state needs to change without referencing the *current* state:
 
 ```js{6,9}
 function Counter() {

content/docs/state-and-lifecycle.md

@@ -244,7 +244,7 @@ Il metodo `componentDidMount()` viene eseguito dopo che l'output del componente
   }
 ```
 
-Nota come salviamo l'ID del timer direttamente in `this`.
+Nota come salviamo l'ID del timer direttamente in `this` (`this.timerID`).
 
 Mentre `this.props` viene impostato da React stesso e `this.state` ha un significato speciale, sei libero di aggiungere altri campi alla classe se hai bisogno di salvare qualcosa che non partecipa al flusso dei dati (come l'ID di un timer).
 

content/docs/thinking-in-react.md

@@ -75,7 +75,8 @@ Fai riferimento alla [Documentazione](/docs/) se hai bisogno di aiuto nell'esecu
 
 ### Un Breve Intervallo: Props vs State {#a-brief-interlude-props-vs-state}
 
-Esistono due tipi di "modello" dati in React: props e state. È importante capire la distinzione tra le due cose; sfoglia [la documentazione ufficiale di React](/docs/interactivity-and-dynamic-uis.html) nel caso avessi dubbi.
+Esistono due tipi di "modello" dati in React: props e state. È importante capire la distinzione tra le due cose; sfoglia [la documentazione ufficiale di React](/docs/state-and-lifecycle.html) nel caso avessi dubbi.
+Puoi leggere inoltre [FAQ: What is the difference between state and props?](/docs/faq-state.html#what-is-the-difference-between-state-and-props)
 
 ## Passo 3: Identifica la Minima (ma completa) Rappresentazione dello Stato della UI {#step-3-identify-the-minimal-but-complete-representation-of-ui-state}
 

content/docs/typechecking-with-proptypes.md

@@ -57,6 +57,9 @@ MyComponent.propTypes = {
   // A React element.
   optionalElement: PropTypes.element,
 
+  // A React element type (ie. MyComponent).
+  optionalElementType: PropTypes.elementType,
+  
   // You can also declare that a prop is an instance of a class. This uses
   // JS's instanceof operator.
   optionalMessage: PropTypes.instanceOf(Message),

content/languages.yml

@@ -10,7 +10,7 @@
 - name: Arabic
   translated_name: العربية
   code: ar
-  status: 0
+  status: 1
 - name: Azerbaijani
   translated_name: Azərbaycanca
   code: az