anchor.diff:  Staging failed: Buildpack compilation step failed
   </pre>
   
  -## <a id='npm_version'></a>Specify an npm Version##
  +## <a id='npm_version'></a>Specify an npm Version ##
   
   To specify an npm version, set `engines.npm` in the `package.json` file to the semantic versioning specification (semver) range or the specific version of npm you are using:
   
  
positive.code: $ yarn install
  </pre>
  
  When you push the app, the buildpack looks for an `npm-packages-offline-cache` directory at the top level of the app directory. If this directory exists, the buildpack runs Yarn in offline mode. Otherwise, it runs Yarn normally, which requires an Internet connection.
  
  For more information about using an offline mirror with Yarn, see the [Yarn Blog](https://yarnpkg.com/blog/2016/11/24/offline-mirror).
  
  
negative.code: Staging failed: Buildpack compilation step failed
  </pre>
  
  ## <a id='using_npm_or_yarn'></a>Using NPM or Yarn ##
  
  By default, the Node.js buildpack assumes you are using NPM. If you would like to use [Yarn](https://yarnpkg.com/) instead, you must provide a [`yarn.lock`](https://yarnpkg.com/lang/en/docs/yarn-lock/) in your top-level app directory.
  
  ## <a id='vendoring'></a>Vendoring App Dependencies ##
  
  To vendor dependencies for an app using the Node.js buildpack, run `npm install` (or `yarn install`, if you are using Yarn) from your app directory. This command vendors dependencies into the `node_modules` directory of your app directory.
  
  For example, the following example vendors dependencies into the `my-nodejs-app/node_modules` directory:
  
  