title: Heroku: "No default language could be detected for this app" error thrown for node app
body: <p>I am learning NodeJS and the course I'm following has several projects, arranged by sections. I have all the projects under one main folder, which is also a <a href="https://github.com/Manish-Giri/Complete-NodeJS-Developer-Course" rel="noreferrer">git repository</a>.</p>
  
  <p>Each of these subfolders in the main folder is a node project by itself, complete with <code>package.json</code> and related dependencies in <code>node_modules</code>. The problem is when I tried to push the node app in one such folder(<code>todo-api</code>) to heroku, I get the following error - </p>
  
  <pre><code>remote: Compressing source files... done.
  remote: Building source:
  remote: 
  remote:  !     No default language could be detected for this app.
  remote:                         HINT: This occurs when Heroku cannot detect the buildpack to use for this application automatically.
  remote:                         See https://devcenter.heroku.com/articles/buildpacks
  remote: 
  remote:  !     Push failed
  remote: Verifying deploy...
  remote: 
  remote: !       Push rejected to agile-forest-32749.
  remote: 
  To https://git.heroku.com/agile-forest-32749.git
   ! [remote rejected] master -&gt; master (pre-receive hook declined)
  error: failed to push some refs to 'https://git.heroku.com/agile-forest-32749.git'
  </code></pre>
  
  <p>This is the directory structure for the project - </p>
  
  <p><a href="https://i.stack.imgur.com/BEOwA.png" rel="noreferrer"><img src="https://i.stack.imgur.com/BEOwA.png" alt="enter image description here"></a></p>
  
  <p>I decided to refactor out the <code>todo-api</code> subfolder into a new project all by itself, and this time the push to Heroku works just fine - </p>
  
  <p><a href="https://i.stack.imgur.com/Dt0pN.png" rel="noreferrer"><img src="https://i.stack.imgur.com/Dt0pN.png" alt="enter image description here"></a></p>
  
  <p>I don't understand why I get the "no default language" error, especially when the node app is exactly the same in both places. Any thoughts?</p>