title: "You seem to not be depending on "@angular/core" and/or "rxjs". This is an error. " when deploying MEAN-app to Heroku
body: <p>I want to deploy my MEAN-stack application using Heroku. I have followed <a href="https://www.youtube.com/watch?v=pDYhwfi7VU0" rel="nofollow noreferrer">this tutorial series</a> mostly to build my app. But when I start deployment by pushing to GIT, it gives me this error during the build process:</p>
  <pre><code>meanstacknieuw@1.0.0 postinstall /tmp/build_837e48e6_
     &gt; cd client &amp;&amp; ng build --aot --prod
     
     You seem to not be depending on &quot;@angular/core&quot; and/or &quot;rxjs&quot;. This is an error.
     npm ERR! code ELIFECYCLE
     npm ERR! errno 2
     npm ERR! meanstacknieuw@1.0.0 postinstall: `cd client &amp;&amp; ng build --aot --prod`
     npm ERR! Exit status 2
     npm ERR! 
     npm ERR! Failed at the meanstacknieuw@1.0.0 postinstall script.
     npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
  </code></pre>
  <p>this is my package.json (of the server side):</p>
  <pre><code>{
    &quot;name&quot;: &quot;meanstacknieuw&quot;,
    &quot;version&quot;: &quot;1.0.0&quot;,
    &quot;description&quot;: &quot;refreshing&quot;,
    &quot;main&quot;: &quot;index.js&quot;,
    &quot;engines&quot;: {
      &quot;node&quot;: &quot;10.16.3&quot;,
      &quot;npm&quot;: &quot;6.11.3&quot;
    },
    &quot;scripts&quot;: {
      &quot;ng&quot;: &quot;ng&quot;,
      &quot;test&quot;: &quot;echo \&quot;Error: no test specified\&quot; &amp;&amp; exit 1&quot;,
      &quot;start&quot;: &quot;node index.js&quot;,
      &quot;build&quot;: &quot;ng build&quot;,
      &quot;heroku-postbuild&quot;: &quot;cd client &amp;&amp; ng build --aot --prod&quot;,
      &quot;postinstall&quot;: &quot;cd client &amp;&amp; ng build --aot --prod&quot;
    },
     &quot;repository&quot;: {
      &quot;type&quot;: &quot;git&quot;,
      &quot;url&quot;: &quot;git+https://github.com/y0u-s/vf-app.git&quot;
    },
    &quot;keywords&quot;: [
      &quot;MEAN&quot;,
      &quot;stack&quot;,
      &quot;angular&quot;,
      &quot;2&quot;,
     &quot;application&quot;
     ],
    &quot;author&quot;: &quot;Youssef&quot;,
     &quot;license&quot;: &quot;ISC&quot;,
     &quot;bugs&quot;: {
      &quot;url&quot;: &quot;https://github.com/y0u-s/latest-mean-stack-app/issues&quot;
    },
    &quot;homepage&quot;: &quot;https://github.com/y0u-s/latest-mean-stack-app#readme&quot;,
    &quot;dependencies&quot;: {
     &quot;@angular/cli&quot;: &quot;^8.3.20&quot;,
      &quot;@angular/compiler&quot;: &quot;^8.2.14&quot;,
      &quot;@angular/compiler-cli&quot;: &quot;^8.2.14&quot;,
     &quot;angular2-flash-messages&quot;: &quot;^3.0.1&quot;,
      &quot;bcrypt&quot;: &quot;^3.0.4&quot;,
      &quot;body-parser&quot;: &quot;^1.18.3&quot;,
   &quot;cors&quot;: &quot;^2.8.5&quot;,
  &quot;express&quot;: &quot;^4.16.4&quot;,
  &quot;file-extension&quot;: &quot;^4.0.5&quot;,
  &quot;jsonwebtoken&quot;: &quot;^8.5.1&quot;,
  &quot;multer&quot;: &quot;^1.4.2&quot;,
  &quot;node-localstorage&quot;: &quot;^2.1.4&quot;,
  &quot;nodemailer&quot;: &quot;^6.4.1&quot;,
  &quot;simple-odata-server&quot;: &quot;^1.1.1&quot;,
  &quot;typescript&quot;: &quot;~3.2.2&quot;
   },
    &quot;devDependencies&quot;: {
  &quot;@angular-devkit/build-angular&quot;: &quot;^0.803.20&quot;
   }
  }
  </code></pre>
  <p>Whats going wrong? Please let me know i you need more context.</p>
  <p>EDIT:</p>
  <pre><code>       -----&gt; Restoring cache
        Cached directories were not restored due to a change in version of 
    node, npm, yarn or stack
     Module installation may take longer for this build
     
     -----&gt; Installing dependencies
     Installing node modules
     npm ERR! cipm can only install packages when your package.json and 
  package-lock.json or npm-shrinkwrap.json are in sync. Please update your lock 
  file with `npm install` before continuing.
     npm ERR! 
     npm ERR! 
     npm ERR! Missing: @angular/rxjs@^8.2.14
     npm ERR! Missing: @angular/core@^8.2.14
     npm ERR! Missing: @angular/common@^8.2.14
     npm ERR! Missing: @angular/platform-browser@^8.2.14
     npm ERR! 
     
  </code></pre>