title: How to fix ERROR TypeError: t.rgb is not a function In ngx-charts heat map graph
body: <p>I'm trying to create a heap map using ngx-charts, the graph is up and running but the colors of the graph is not shown because of an RGB error in the library. Any suggestions to solve this issue? </p>
  
  <p>Here is an Image of the chart with no colors. These bars should be filled with colors. Found that <code>d3js</code> is used as a dependency on ngx-charts </p>
  
  <p><a href="https://i.stack.imgur.com/ZG8zs.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ZG8zs.jpg" alt="enter image description here"></a></p>
  
  <p>Error message in console - </p>
  
  <pre><code>main-es2015.c512fe386c6a4d3e4777.js:1 ERROR TypeError: t.rgb is not a function
      at _ (main-es2015.c512fe386c6a4d3e4777.js:1)
      at w (main-es2015.c512fe386c6a4d3e4777.js:1)
      at i (main-es2015.c512fe386c6a4d3e4777.js:1)
      at b (main-es2015.c512fe386c6a4d3e4777.js:1)
      at y (main-es2015.c512fe386c6a4d3e4777.js:1)
      at t.f [as scale] (main-es2015.c512fe386c6a4d3e4777.js:1)
      at t.getColor (main-es2015.c512fe386c6a4d3e4777.js:1)
      at main-es2015.c512fe386c6a4d3e4777.js:1
      at Array.map (&lt;anonymous&gt;)
      at main-es2015.c512fe386c6a4d3e4777.js:1
  </code></pre>
  
  <p>Link for the issue in GitHub - <a href="https://github.com/swimlane/ngx-charts/issues/1291" rel="nofollow noreferrer">link to issue</a></p>