title: Impossible to push to Heroku - Push rejected, failed to compile Node.js app
body: <p>I don't know why but it's impossible to push on Heroku. 
  I don't found the error :/. 
  Thanks for the help ^^.</p>
  
  <p>It's an express application with React client (use compass)</p>
  
  <p>BuildPack -> <a href="https://github.com/stephanmelzer/heroku-buildpack-nodejs-grunt-compass.git" rel="nofollow noreferrer">https://github.com/stephanmelzer/heroku-buildpack-nodejs-grunt-compass.git</a></p>
  
  <pre><code>-----&gt; Node.js app detected
  -----&gt; Creating runtime environment
  
         NPM_CONFIG_LOGLEVEL=error
         NODE_VERBOSE=false
         NODE_ENV=production
         NODE_MODULES_CACHE=true
  -----&gt; Installing binaries
         engines.node (package.json):  9.11.1
         engines.npm (package.json):   unspecified (use default)
  
         Resolving node version 9.11.1...
         Downloading and installing node 9.11.1...
         Using default npm version: 5.6.0
  -----&gt; Restoring cache
         Skipping cache restore (new-signature)
  -----&gt; Building dependencies
         Installing node modules (package.json + package-lock)
         added 365 packages in 8.599s
  -----&gt; Caching build
         Clearing previous node cache
         Saving 2 cacheDirectories (default):
         - node_modules
         - bower_components (nothing to cache)
  -----&gt; Pruning devDependencies
         Skipping because npm 5.6.0 sometimes fails when running 'npm prune' due to a known issue
         https://github.com/npm/npm/issues/19356
  
         You can silence this warning by updating to at least npm 5.7.1 in your package.json
         https://devcenter.heroku.com/articles/nodejs-support#specifying-an-npm-version
  -----&gt; Build succeeded!
  -----&gt; Node.js app detected
  -----&gt; Requested node range:  9.11.1
  -----&gt; Resolved node version: 9.11.1
  -----&gt; Downloading and installing node
   !     Push rejected, failed to compile Node.js app.
   !     Push failed
  </code></pre>