title: How to find all layers in Mapboxgl ? Ultimately I want to show custom layer only on water and not on land
body: <p>I created a custom circle layer. I want to show this layer only on water and not on land. I managed to do the opposite (ie: showing the layer on land and not on water) using below command. <a href="https://i.stack.imgur.com/CJL1z.png" rel="noreferrer">Refer this image for better understanding</a> </p>
  
  <blockquote>
    <p>map.moveLayer('polygon','water');</p>
  </blockquote>
  
  <p>Now I need to know the land layer which is used by mapboxgl so that I can call function <code>map.moveLayer('polygon','land');</code> to achieve what i want.</p>
  
  <p>I need help to find the different layers present in the mapboxgl-streets map. But unfortunately, Mapboxgl doesn't have map.eachLayer function.</p>