Preact example doesn't start or build

[rafaelalmeidatk]

Examples bug report

Example name

using-preact

Describe the bug

When trying to run yarn dev the example breaks with the error:

$ node server.js
/home/rafael/projects/next.js/examples/using-preact/node_modules/next/dist/next-server/lib/amp-context.js:11
exports.AmpStateContext = React.createContext({});
                                ^

TypeError: React.createContext is not a function
    at Object.<anonymous> (/home/rafael/projects/next.js/examples/using-preact/node_modules/next/dist/next-server/lib/amp-context.js:11:33)
    at Module._compile (internal/modules/cjs/loader.js:776:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:787:10)
    at Module.load (internal/modules/cjs/loader.js:653:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
    at Function.Module._load (internal/modules/cjs/loader.js:585:3)
    at Module.require (internal/modules/cjs/loader.js:690:17)
    at require (internal/modules/cjs/helpers.js:25:18)
    at Object.<anonymous> (/home/rafael/projects/next.js/examples/using-preact/node_modules/next/dist/next-server/lib/head.js:8:23)
    at Module._compile (internal/modules/cjs/loader.js:776:30)
error Command failed with exit code 1.

To Reproduce

1. Go to examples/using-preact
2. Run yarn install && yarn dev
3. See error

Expected behavior

The app should start successfully

System information

• OS: Ubuntu 19.04
• Version of Next.js: 9.1.1

Additional context

createContext is already built-in on the latest version of Preact (Preact X), it could be as simple as updating it, but then comes the second problem: you cannot run yarn build without react and react-dom installed in the project:

$ next build
The module 'react' was not found. Next.js requires that you include it in 'dependencies' of your 'package.json'. To add it, run 'npm install --save react'
The module 'react-dom' was not found. Next.js requires that you include it in 'dependencies' of your 'package.json'. To add it, run 'npm install --save react-dom'
internal/modules/cjs/loader.js:638
    throw err;
    ^

Error: Cannot find module 'react'
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:636:15)
    at Function.Module._load (internal/modules/cjs/loader.js:562:25)
    at Module.require (internal/modules/cjs/loader.js:690:17)
    at require (internal/modules/cjs/helpers.js:25:18)
    at Object.<anonymous> (/home/rafael/projects/next.js/examples/using-preact/node_modules/next/dist/bin/next:29:13)
    at Module._compile (internal/modules/cjs/loader.js:776:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:787:10)
    at Module.load (internal/modules/cjs/loader.js:653:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
    at Function.Module._load (internal/modules/cjs/loader.js:585:3)
error Command failed with exit code 1.

Does the project need to have react and react-dom installed to be built, even if it is already using Preact, or is there a way to alias these modules to the build step like we do in next.config.js?

[balazsorban44]

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