title: Index handler is undefined or not exported
body: <p>I have a lambda function which was working fine but I wanted to import a package so I created a directory with index.js and installed my npm package. </p>
  
  <p>Then created a zip of this folder and uploaded it using </p>
  
  <blockquote>
    <p>aws lambda update-function-code --function-name smrtfac-test
    --zip-file fileb://lambda.zip</p>
  </blockquote>
  
  <p>But now I am getting this error </p>
  
  <pre><code>index.handler is undefined or not exported
  </code></pre>
  
  <p>What could be the reason for it?
  my <code>index.js</code> and <code>node_modules</code> are in the same directory.</p>