title: How to create a react build pipeline in vsts with yarn. Couldn't find a package.json
body: <p>I have a react project, and locally I use just yarn install, yarn build and yarn start to test it at <a href="https://localhost:3000" rel="nofollow noreferrer">https://localhost:3000</a></p>
  
  <p>I have the following pipeline:
  <a href="https://i.stack.imgur.com/PDM2N.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/PDM2N.png" alt="enter image description here"></a></p>
  
  <p>However I have this error in the logs:</p>
  
  <pre><code>2018-08-10T08:31:34.6206910Z ##[section]Starting: Yarn build
  2018-08-10T08:31:34.6211162Z ==============================================================================
  2018-08-10T08:31:34.6211307Z Task         : Yarn task
  2018-08-10T08:31:34.6211411Z Description  : Executes Yarn
  2018-08-10T08:31:34.6211531Z Version      : 2.5.999
  2018-08-10T08:31:34.6211633Z Author       : Geek Learning
  2018-08-10T08:31:34.6211842Z Help         : [More Information](https://github.com/geeklearningio/gl-vsts-tasks-yarn/wiki/Yarn) (Version 2.5.999).
  
  Dear Angular and Ember CLI users, please check our [known issues](https://github.com/geeklearningio/gl-vsts-tasks-yarn/wiki/Known-Issues)
  2018-08-10T08:31:34.6212057Z ==============================================================================
  2018-08-10T08:31:35.2261051Z [command]C:\Windows\system32\cmd.exe /D /S /C "C:\hostedtoolcache\windows\yarn\1.9.4\x64\yarn-v1.9.4\bin\yarn.cmd build"
  2018-08-10T08:31:42.0864621Z yarn run v1.9.4
  2018-08-10T08:31:42.1571684Z error Couldn't find a package.json file in "C:\\"
  2018-08-10T08:31:42.1572901Z info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
  2018-08-10T08:31:42.1822978Z ##[error]Error: C:\hostedtoolcache\windows\yarn\1.9.4\x64\yarn-v1.9.4\bin\yarn.cmd failed with return code: 1
  2018-08-10T08:31:42.1893252Z ##[section]Finishing: Yarn build
  </code></pre>
  
  <p>But there is actually a package.json</p>
  
  <p><a href="https://i.stack.imgur.com/d95Us.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/d95Us.png" alt="enter image description here"></a></p>