Merge branch 'master' into portals-page

Author: nooblyf

content/community/conferences.md

@@ -18,15 +18,10 @@ March 30 - 31, 2020 in San Francisco, CA
 [Website](https://www.reactathon.com) - [Twitter](https://twitter.com/reactathon) - [Facebook](https://www.facebook.com/events/575942819854160/)
 
 ### React Summit Amsterdam 2020 {#react-summit-2020}
-April 15-17, 2020 in Amsterdam, The Netherlands
+September 11, 2020 in Amsterdam, The Netherlands
 
 [Website](https://reactsummit.com) - [Twitter](https://twitter.com/reactamsterdam) - [Facebook](https://www.facebook.com/reactamsterdam) - [Videos](https://youtube.com/c/ReactConferences)
 
-### App.js Conf 2020 {#appjsonf2020}
-April 23 - 24, 2020 in Kraków, Poland
-
-[Website](http://appjs.co/react) - [Twitter](https://twitter.com/appjsconf)
-
 ### React Day Bangalore 2020 {#react-day-bangalore-2020}
 April 25, 2020 in Bangalore, India
 

content/docs/code-splitting.md

@@ -97,7 +97,7 @@ import("./math").then(math => {
 When Webpack comes across this syntax, it automatically starts code-splitting
 your app. If you're using Create React App, this is already configured for you
 and you can [start using it](https://facebook.github.io/create-react-app/docs/code-splitting) immediately. It's also supported
-out of the box in [Next.js](https://github.com/zeit/next.js/#dynamic-import).
+out of the box in [Next.js](https://nextjs.org/docs/advanced-features/dynamic-import).
 
 If you're setting up Webpack yourself, you'll probably want to read Webpack's
 [guide on code splitting](https://webpack.js.org/guides/code-splitting/). Your Webpack config should look vaguely [like this](https://gist.github.com/gaearon/ca6e803f5c604d37468b0091d9959269).

content/docs/strict-mode.md

@@ -97,13 +97,13 @@ Render phase lifecycles include the following class component methods:
 
 Because the above methods might be called more than once, it's important that they do not contain side-effects. Ignoring this rule can lead to a variety of problems, including memory leaks and invalid application state. Unfortunately, it can be difficult to detect these problems as they can often be [non-deterministic](https://en.wikipedia.org/wiki/Deterministic_algorithm).
 
-Strict mode can't automatically detect side effects for you, but it can help you spot them by making them a little more deterministic. This is done by intentionally double-invoking the following methods:
+Strict mode can't automatically detect side effects for you, but it can help you spot them by making them a little more deterministic. This is done by intentionally double-invoking the following functions:
 
-* Class component `constructor` method
-* The `render` method
-* `setState` updater functions (the first argument)
-* The static `getDerivedStateFromProps` lifecycle
-* The `shouldComponentUpdate` method
+* Class component `constructor`, `render`, and `shouldComponent` methods
+* Class component static `getDerivedStateFromProps` method
+* Function component bodies
+* State updater functions (the first argument to `setState`)
+* Functions passed to `useState`, `useMemo`, or `useReducer`
 
 > Note:
 >