Merge branch 'canary' into IMAGE_NO_JS_FALLBACK

.github/CODEOWNERS

@@ -1,6 +1,6 @@
 # Learn how to add code owners here:
 # https://help.github.com/en/articles/about-code-owners
 
-*          @timneutkens @Timer @ijjk @lfades @divmain
-/docs/     @timneutkens @Timer @ijjk @lfades @divmain @leerob
-/examples/ @timneutkens @Timer @ijjk @lfades @divmain @leerob
+*          @timneutkens @ijjk @lfades @divmain @shuding
+/docs/     @timneutkens @ijjk @lfades @divmain @shuding @leerob
+/examples/ @timneutkens @ijjk @lfades @divmain @shuding @leerob

.github/pull_request_template.md

@@ -0,0 +1,22 @@
+<!--
+Thanks for opening a PR! Your contribution is much appreciated.
+In order to make sure your PR is handled as smoothly as possible we request that you follow the checklist sections below.
+Choose the right checklist for the change that you're making:
+-->
+
+## Bug
+
+- [ ] Related issues linked using `fixes #number`
+- [ ] Integration tests added
+
+## Feature
+
+- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
+- [ ] Related issues linked using `fixes #number`
+- [ ] Integration tests added
+- [ ] Documentation added
+- [ ] Telemetry added. In case of a feature if it's used or not.
+
+## Documentation / Examples
+
+- [ ] Make sure the linting passes

contributing.md

@@ -3,7 +3,7 @@
 Our Commitment to Open Source can be found [here](https://vercel.com/oss).
 
 1. [Fork](https://help.github.com/articles/fork-a-repo/) this repository to your own GitHub account and then [clone](https://help.github.com/articles/cloning-a-repository/) it to your local device.
-2. Create a new branch `git checkout -b MY_BRANCH_NAME`
+2. Create a new branch: `git checkout -b MY_BRANCH_NAME`
 3. Install yarn: `npm install -g yarn`
 4. Install the dependencies: `yarn`
 5. Run `yarn dev` to build and watch for code changes

docs/advanced-features/custom-server.md

@@ -15,7 +15,7 @@ description: Start a Next.js app programmatically using a custom server.
   </ul>
 </details>
 
-Typically you start your next server with `next start`. It's possible, however, to start a server 100% programmatically in order to use custom route patterns.
+By default, Next.js includes its own server with `next start`. If you have an existing backend, you can still use it with Next.js (this is not a custom server). A custom Next.js server allows you to start a server 100% programmatically in order to use custom server patterns. Most of the time, you will not need this – but it's available for complete customization.
 
 > A custom server **can not** be deployed on [Vercel](https://vercel.com/solutions/nextjs), the platform Next.js was made for.
 

docs/advanced-features/preview-mode.md

@@ -16,6 +16,7 @@ description: Next.js has the preview mode for statically generated pages. You ca
     <li><a href="https://github.com/vercel/next.js/tree/canary/examples/cms-prismic">Prismic Example</a> (<a href="https://next-blog-prismic.now.sh/">Demo</a>)</li>
     <li><a href="https://github.com/vercel/next.js/tree/canary/examples/cms-contentful">Contentful Example</a> (<a href="https://next-blog-contentful.now.sh/">Demo</a>)</li>
     <li><a href="https://github.com/vercel/next.js/tree/canary/examples/cms-strapi">Strapi Example</a> (<a href="https://next-blog-strapi.now.sh/">Demo</a>)</li>
+    <li><a href="https://github.com/vercel/next.js/tree/canary/examples/cms-prepr">Prepr Example</a> (<a href="https://next-blog-prepr.now.sh/">Demo</a>)</li>    
     <li><a href="https://github.com/vercel/next.js/tree/canary/examples/cms-agilitycms">Agility CMS Example</a> (<a href="https://next-blog-agilitycms.now.sh/">Demo</a>)</li>
     <li><a href="https://github.com/vercel/next.js/tree/canary/examples/cms-cosmic">Cosmic Example</a> (<a href="https://next-blog-cosmic.now.sh/">Demo</a>)</li>
     <li><a href="https://github.com/vercel/next.js/tree/canary/examples/cms-buttercms">ButterCMS Example</a> (<a href="https://next-blog-buttercms.now.sh/">Demo</a>)</li>

docs/api-reference/next.config.js/introduction.md

@@ -44,7 +44,7 @@ module.exports = (phase, { defaultConfig }) => {
 }
 ```
 
-The commented lines are the place where you can put the configs allowed by `next.config.js`, which are defined [here](https://github.com/vercel/next.js/blob/canary/packages/next/next-server/server/config.ts#L12-L63).
+The commented lines are the place where you can put the configs allowed by `next.config.js`, which are defined [here](https://github.com/vercel/next.js/blob/canary/packages/next/next-server/server/config-shared.ts#L33).
 
 However, none of the configs are required, and it's not necessary to understand what each config does. Instead, search for the features you need to enable or modify in this section and they will show you what to do.
 

docs/authentication.md

@@ -119,10 +119,8 @@ Now that we've discussed authentication patterns, let's look at specific provide
 
 If you have an existing database with user data, you'll likely want to utilize an open-source solution that's provider agnostic.
 
-- If you need email/password log-in, use [`next-iron-session`](https://github.com/vercel/next.js/tree/canary/examples/with-iron-session).
-- If you need to persist session data on the server, use [`next-auth`](https://github.com/nextauthjs/next-auth-example).
-- If you need to support social login (Google, Facebook, etc.), use [`next-auth`](https://github.com/nextauthjs/next-auth-example).
-- If you want to use [JWTs](https://jwt.io/), use [`next-auth`](https://github.com/nextauthjs/next-auth-example).
+- If you want a low-level, encrypted, and stateless session utility use [`next-iron-session`](https://github.com/vercel/next.js/tree/canary/examples/with-iron-session).
+- If you want a full-featured authentication system with built-in providers (Google, Facebook, GitHub…), JWT, JWE, email/password, magic links and more… use [`next-auth`](https://github.com/nextauthjs/next-auth-example).
 
 Both of these libraries support either authentication pattern. If you're interested in [Passport](http://www.passportjs.org/), we also have examples for it using secure and encrypted cookies:
 

docs/basic-features/data-fetching.md

@@ -17,6 +17,7 @@ description: 'Next.js has 2 pre-rendering modes: Static Generation and Server-si
     <li><a href="https://github.com/vercel/next.js/tree/canary/examples/cms-prismic">Prismic Example</a> (<a href="https://next-blog-prismic.now.sh/">Demo</a>)</li>
     <li><a href="https://github.com/vercel/next.js/tree/canary/examples/cms-contentful">Contentful Example</a> (<a href="https://next-blog-contentful.now.sh/">Demo</a>)</li>
     <li><a href="https://github.com/vercel/next.js/tree/canary/examples/cms-strapi">Strapi Example</a> (<a href="https://next-blog-strapi.now.sh/">Demo</a>)</li>
+    <li><a href="https://github.com/vercel/next.js/tree/canary/examples/cms-prepr">Prepr Example</a> (<a href="https://next-blog-prepr.now.sh/">Demo</a>)</li>
     <li><a href="https://github.com/vercel/next.js/tree/canary/examples/cms-agilitycms">Agility CMS Example</a> (<a href="https://next-blog-agilitycms.now.sh/">Demo</a>)</li>
     <li><a href="https://github.com/vercel/next.js/tree/canary/examples/cms-cosmic">Cosmic Example</a> (<a href="https://next-blog-cosmic.now.sh/">Demo</a>)</li>
     <li><a href="https://github.com/vercel/next.js/tree/canary/examples/cms-buttercms">ButterCMS Example</a> (<a href="https://next-blog-buttercms.now.sh/">Demo</a>)</li>
@@ -355,6 +356,8 @@ When a page with `getStaticProps` is pre-rendered at build time, in addition to
 
 This JSON file will be used in client-side routing through `next/link` ([documentation](/docs/api-reference/next/link.md)) or `next/router` ([documentation](/docs/api-reference/next/router.md)). When you navigate to a page that’s pre-rendered using `getStaticProps`, Next.js fetches this JSON file (pre-computed at build time) and uses it as the props for the page component. This means that client-side page transitions will **not** call `getStaticProps` as only the exported JSON is used.
 
+When using Incremental Static Generation `getStaticProps` will be executed out of band to generate the JSON needed for client-side navigation. You may see this in the form of multiple requests being made for the same page, however, this is intended and has no impact on end-user performance
+
 #### Only allowed in a page
 
 `getStaticProps` can only be exported from a **page**. You can’t export it from non-page files.

docs/basic-features/pages.md

@@ -56,6 +56,7 @@ You can also use **Client-side Rendering** along with Static Generation or Serve
     <li><a href="https://github.com/vercel/next.js/tree/canary/examples/cms-prismic">Prismic Example</a> (<a href="https://next-blog-prismic.now.sh/">Demo</a>)</li>
     <li><a href="https://github.com/vercel/next.js/tree/canary/examples/cms-contentful">Contentful Example</a> (<a href="https://next-blog-contentful.now.sh/">Demo</a>)</li>
     <li><a href="https://github.com/vercel/next.js/tree/canary/examples/cms-strapi">Strapi Example</a> (<a href="https://next-blog-strapi.now.sh/">Demo</a>)</li>
+    <li><a href="https://github.com/vercel/next.js/tree/canary/examples/cms-prepr">Prepr Example</a> (<a href="https://next-blog-prepr.now.sh/">Demo</a>)</li>    
     <li><a href="https://github.com/vercel/next.js/tree/canary/examples/cms-agilitycms">Agility CMS Example</a> (<a href="https://next-blog-agilitycms.now.sh/">Demo</a>)</li>
     <li><a href="https://github.com/vercel/next.js/tree/canary/examples/cms-cosmic">Cosmic Example</a> (<a href="https://next-blog-cosmic.now.sh/">Demo</a>)</li>
     <li><a href="https://github.com/vercel/next.js/tree/canary/examples/cms-buttercms">ButterCMS Example</a> (<a href="https://next-blog-buttercms.now.sh/">Demo</a>)</li>

docs/migrating/from-create-react-app.md

@@ -199,12 +199,12 @@ export default function SEO({ description, title, siteTitle }) {
 
 ## Single-Page App (SPA)
 
-If you want to move your existing Create React App to Next.js and keep a Single-Page App, you can move your old application entry point to an [Optional Catch-All Route](/docs/routing/dynamic-routes.md#optional-catch-all-routes) named `pages/[[…app]].js`.
+If you want to move your existing Create React App to Next.js and keep a Single-Page App, you can move your old application's entry point to an [Optional Catch-All Route](/docs/routing/dynamic-routes.md#optional-catch-all-routes) named `pages/[[…app]].js`.
 
 ```jsx
 // pages/[[...app]].js
 
-import { useState } from 'react'
+import { useState, useEffect } from 'react'
 import CreateReactAppEntryPoint from '../components/app'
 
 function App() {