AMap.Geocoder is not a constructor

The error "AMap.Geocoder is not a constructor" typically occurs when the AMap JavaScript library is not properly loaded or initialized.

To fix this error, make sure that you have included the AMap JavaScript library in your HTML file and that it is loaded before you try to use the AMap.Geocoder constructor. You can include the library using a script tag like this:

<script src="https://webapi.amap.com/maps?v=1.4.15&key=YOUR_API_KEY"></script>

Replace `YOUR_API_KEY` with your actual AMap API key.

Once you have included the library, make sure that it is loaded before you try to use the AMap.Geocoder constructor. You can do this by wrapping your code in a window.onload function like this:

window.onload = function() {
  // Your AMap code here...
};

This ensures that your code will only execute after the page has finished loading and the AMap library is fully initialized.