- Implements Lerna
- Moves all source code into `packages/next`
- Keeps integration tests in the root directory

- `<details>` and `<ul>` cannot be inside `<p>` and it will not be parsed correctly by the MDX tokenizer.
- `sh` is not a valid language name for syntax highlighting libs (e.g. [highlight.js](https://github.com/highlightjs/highlight.js/tree/master/src/languages)).

We don't need to `React.cloneElement`, twice.

This PR removes the obsolete `_containerProps` context.

### Next js 7+ and Typescript 3+ Example

No babel, tsc, pure typescript usage
Made by [next-with-typescript plugin](https://github.com/echoulen/next-with-typescript)

* Remove obsolete check in dev-server

* Don’t require package.json at runtime

Inline the Next.js version at publish time, so that there’s no runtime dependency for this

Remove `if(this.hotReloader)` as it's always guaranteed to be there.

https://github.com/zeit/next.js/pull/5317#discussion_r221233064

* Initial dev server

* Remove obsolete check

* Move hotReloader to dev-server

* Use parent renderErrorToHTML to remove dep on render.js

* Remove dev option from server itself

* show warning if there is a title in _document.js Head

* dont loop through children in production

* only 1 loop through this.props.children 💪

* also raise warning in test env

* check for null childs

- This makes sure the Next.js renderer / server doesn't have a dependency on the `http` module.
- Splits out util functions for SSR only
- Removes obsolete methods / methods that weren't being tree-shaken

To work with babel7 & next7.

* [with-typescript] Updated `@zeit/next-typescript` and typescript typings

* [with-typescript] Updated tsconfig to match new recommended config

* [with-typescript] upgraded dependencies, implement type-checking

* [with-typescript] add _document example, fixed tsconfig

* [with-typescript] updated README

* [with-typescript] updated example contents

* [with-typescript] adopt the Layout component from Flow example

An upstream bug in webpack-dev-middleware caused unhandled rejections to be swallowed.

Since version 2.1, react-apollo is exposing some new components that use the function-as-child (or render-prop) pattern to let you connect apollo-client magic with your components. See the blog article: [New in React Apollo 2.1](https://www.apollographql.com/docs/react/react-apollo-migration.html)

If I'm not mistaken, it's generally agreed that this pattern is (where it works) superior to the HOC pattern, for reasons that are best explained here: https://cdb.reacttraining.com/use-a-render-prop-50de598f11ce 

So I updated the with-apollo example to use the new API, and IMO this code is much simpler and natural to read and understand, especially if you are not already familiar with Apollo's HOC APIs.

I broke up my changes into separate commits, for easier review. Commits with "Refactor" in the message accomplish the goal of switching to the new APIs while minimizing line-by-line differences (select "Hide whitespace changes" under "Diff settings"). Commits with "Clean up" in the message follow up the refactoring with trivial things like reorganizing code sections, renaming variables, etc.

For the components doing mutations, I chose not to use the `Mutation` component, since that doesn't really make sense to me; a mutation is something that happens at a point in time, so it's not meaningful to represent a mutation in the markup, which exists for a period of time. All that component does is expose a `mutate` function for a single specified mutation, and `result` data for a single firing of the mutation (which we don't need anyways; apollo handles updating the local data with the result). To me it seems simpler and more flexible to just get the apollo client via `ApolloConsumer` and call `.mutate()` on it. 

In case anyone is interested, here's what my version of `PostUpvoter` using the `Mutation` component looked like:

 <details>

```jsx
import React from 'react'
import { Mutation } from 'react-apollo'
import { gql } from 'apollo-boost'

export default function PostUpvoter ({ votes, id }) {
  return (
    <Mutation mutation={upvotePost}>
      {mutate => (
        <button onClick={() => upvote(id, votes + 1, mutate)}>
          {votes}
          <style jsx>{`
            button {
              background-color: transparent;
              border: 1px solid #e4e4e4;
              color: #000;
            }
            button:active {
              background-color: transparent;
            }
            button:before {
              align-self: center;
              border-color: transparent transparent #000000 transparent;
              border-style: solid;
              border-width: 0 4px 6px 4px;
              content: '';
              height: 0;
              margin-right: 5px;
              width: 0;
            }
          `}</style>
        </button>
      )}
    </Mutation>
  )
}

const upvotePost = gql`
  mutation updatePost($id: ID!, $votes: Int) {
    updatePost(id: $id, votes: $votes) {
      id
      __typename
      votes
    }
  }
`
function upvote (id, votes, mutate) {
  mutate({
    variables: { id, votes },
    optimisticResponse: {
      __typename: 'Mutation',
      updatePost: {
        __typename: 'Post',
        id,
        votes
      }
    }
  })
}
```

</details>

###

I'm happy with where things are at here, but I'm more than happy to address any comments, concerns, ideas for improvent!

Thanks!

As they were failing intermittently, this PR tries to solve that.

* Add failing tests

* Upgrade wd module

* Pass dynamic import webpack ids to the client side

* Pass through webpack ids to initalializer and only use those

* Compile dynamic(import()) to dynamic(() => import())

* Default dynamicIds

* Use forked hard-source-plugin

* Possibly fix test

* Make tests fail less intermittently

* Temporarily disable hard-source in production

* Make sure dynamic import chunks are unique

* Disable hard-source

* Log html if error is thrown

* Fix test

This fixes https://github.com/zeit/next.js/issues/5260 by making sure that `index.js` has `getInitialProps` defined on the page exported component, not the child component.

When fixing that, I uncovered an issue where the server side rendered HTML did not match the clientside HTML, so I reworked _app.js to use the `i18nextprovider` component which has props to hydrate the initial data (for SSR), and makes sure the correct i18n instance is passed to all child components through context.

Before:
```html
<!DOCTYPE html>
<html>
   <head>
      <meta charSet="utf-8" class="next-head"/>
      <link rel="preload" href="/_next/static/development/pages/index.js" as="script"/>
      <link rel="preload" href="/_next/static/development/pages/_app.js" as="script"/>
      <link rel="preload" href="/_next/static/development/pages/_error.js" as="script"/>
      <link rel="preload" href="/_next/static/runtime/webpack.js" as="script"/>
      <link rel="preload" href="/_next/static/runtime/main.js" as="script"/>
   </head>
   <body>
      <div id="__next"></div>
      <script src="/_next/static/development/dll/dll_4a2ab6ce0cb456fbfead.js"></script><script>__NEXT_DATA__ = {"props":{"pageProps":{}},"page":"/","pathname":"/","query":{},"buildId":"development"};__NEXT_LOADED_PAGES__=[];__NEXT_REGISTER_PAGE=function(r,f){__NEXT_LOADED_PAGES__.push([r, f])}</script><script async="" id="__NEXT_PAGE__/" src="/_next/static/development/pages/index.js"></script><script async="" id="__NEXT_PAGE__/_app" src="/_next/static/development/pages/_app.js"></script><script async="" id="__NEXT_PAGE__/_error" src="/_next/static/development/pages/_error.js"></script><script src="/_next/static/runtime/webpack.js" async=""></script><script src="/_next/static/runtime/main.js" async=""></script>
   </body>
</html>
```

After: 
```html
<!DOCTYPE html>
<html>
   <head>
      <meta charSet="utf-8" class="next-head"/>
      <link rel="preload" href="/_next/static/development/pages/index.js" as="script"/>
      <link rel="preload" href="/_next/static/development/pages/_app.js" as="script"/>
      <link rel="preload" href="/_next/static/development/pages/_error.js" as="script"/>
      <link rel="preload" href="/_next/static/runtime/webpack.js" as="script"/>
      <link rel="preload" href="/_next/static/runtime/main.js" as="script"/>
   </head>
   <body>
      <div id="__next">
         <h1>This example integrates react-i18next for simple internationalization.</h1>
         <div>
            <h1>welcome to next.js</h1>
            <p>This example integrates react-i18next for simple internationalization.</p>
            <p>test words for en</p>
            <div><button>fire in the wind for en</button></div>
            <p>You can either pass t function to child components.</p>
            <p>Or wrap your component using the translate hoc provided by react-i18next.</p>
            <p>Alternatively, you can use <code>Trans</code> component.</p>
            <a href="/page2">Go to page 2</a><br/><a href="/page3">Go to page 3 (no hoc)</a>
         </div>
      </div>
      <script src="/_next/static/development/dll/dll_4a2ab6ce0cb456fbfead.js"></script><script>__NEXT_DATA__ = {"props":{"pageProps":{"i18n":null,"initialI18nStore":{"en":{"home":{"welcome":"welcome to next.js","sample_test":"test words for en","sample_button":"fire in the wind for en","link":{"gotoPage2":"Go to page 2","gotoPage3":"Go to page 3 (no hoc)"}},"common":{"integrates_react-i18next":"This example integrates react-i18next for simple internationalization.","pureComponent":"You can either pass t function to child components.","extendedComponent":"Or wrap your component using the translate hoc provided by react-i18next.","transComponent":"Alternatively, you can use \u003c1\u003eTrans\u003c/1\u003e component."}}},"initialLanguage":"en-US"}},"page":"/","pathname":"/","query":{},"buildId":"development"};__NEXT_LOADED_PAGES__=[];__NEXT_REGISTER_PAGE=function(r,f){__NEXT_LOADED_PAGES__.push([r, f])}</script><script async="" id="__NEXT_PAGE__/" src="/_next/static/development/pages/index.js"></script><script async="" id="__NEXT_PAGE__/_app" src="/_next/static/development/pages/_app.js"></script><script async="" id="__NEXT_PAGE__/_error" src="/_next/static/development/pages/_error.js"></script><script src="/_next/static/runtime/webpack.js" async=""></script><script src="/_next/static/runtime/main.js" async=""></script>
   </body>
</html>
```

* Update .babelrc

babel-plugin-transform-decorators-legacy does not exist in babel 7 in replace use @babel/plugin-proposal-decorators

* Update package.json

Acording the last commit please,  test this example , will be work .

Trivial note to remind anyone doing sentry that they should consider doing server side logging too.

Noting per https://github.com/zeit/next.js/issues/5050 for new users of Apollo that they should not be concerned about multiple renders.