[Docs] cell-class Function

<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <title>ZingGrid: Blank Grid</title>
  <script nonce="undefined" src="https://cdn.zinggrid.com/dev/zinggrid-dev.min.js"></script>
  <style>
    body {
      background: #e6e6e6;
    }

    .breed {
      background: #fff59d;
    }

    .cane-corso {
      background: #ef9a9a;
    }

    .pomeranian {
      background: #90caf9;
    }

    .name {
      font-family: Roboto;
    }

    .ziva {
      font-size: 2rem;
    }

    .koda {
      font-size: 1.3rem;
    }

    zing-grid[loading] {
      height: 552px;
    }
  </style>
</head>

<body>
  <!-- Most features can be toggled on the toplevel zing-grid tag -->
  <zing-grid caption="Cell Class Function" layout="row" layout-controls="disabled" viewport-stop>
    <!-- dataset -->
    <zg-data data='[
      	{ "breed": "Cane Corso", "name": "Ziva"},
      	{ "breed": "Pug", "name": "Doug"},
      	{ "breed": "Corgi", "name": "Jenny"},
      	{ "breed": "Pomeranian", "name": "Koda"},
      	{ "breed": "Great Dane", "name": "Zeus"},
      	{ "breed": "Frenchie", "name": "Bruce"},
      	{ "breed": "Cane Corso", "name": "Sofia"},
      	{ "breed": "Pomeranian", "name": "Snowball"}
      ]'></zg-data>

    <!-- define custom columns -->
    <zg-colgroup>
      <zg-column index="breed" cell-class="singleIndex"></zg-column>
      <zg-column index="name, breed" cell-class="multipleIndices"></zg-column>
    </zg-colgroup>
  </zing-grid>

  <script>
    ZingGrid.setLicense(['26ccbfec16b8be9ee98c7d57bee6e498']);

    function singleIndex(breed, cellDOMRef, cellRef) {
      return `breed ${breed.replace(/\s+/g, '-').toLowerCase()}`;
    }

    function multipleIndices(name, breed, cellDOMRef, cellRef) {
      return `name ${name.toLowerCase()}`;
    }
  </script>
</body>

</html>

<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <title>ZingGrid: Blank Grid</title>
  <script src="https://cdn.zinggrid.com/dev/zinggrid-dev.min.js"></script>
</head>

<body>
  <!-- Most features can be toggled on the toplevel zing-grid tag -->
  <zing-grid caption="Cell Class Function" layout="row" layout-controls="disabled" viewport-stop>
    <!-- dataset -->
    <zg-data data='[
      	{ "breed": "Cane Corso", "name": "Ziva"},
      	{ "breed": "Pug", "name": "Doug"},
      	{ "breed": "Corgi", "name": "Jenny"},
      	{ "breed": "Pomeranian", "name": "Koda"},
      	{ "breed": "Great Dane", "name": "Zeus"},
      	{ "breed": "Frenchie", "name": "Bruce"},
      	{ "breed": "Cane Corso", "name": "Sofia"},
      	{ "breed": "Pomeranian", "name": "Snowball"}
      ]'></zg-data>

    <!-- define custom columns -->
    <zg-colgroup>
      <zg-column index="breed" cell-class="singleIndex"></zg-column>
      <zg-column index="name, breed" cell-class="multipleIndices"></zg-column>
    </zg-colgroup>
  </zing-grid>

</body>

</html>

body {
  background: #e6e6e6;
}

.breed {
  background: #fff59d;
}

.cane-corso {
  background: #ef9a9a;
}

.pomeranian {
  background: #90caf9;
}

.name {
  font-family: Roboto;
}

.ziva {
  font-size: 2rem;
}

.koda {
  font-size: 1.3rem;
}

function singleIndex(breed, cellDOMRef, cellRef) {
  return `breed ${breed.replace(/\s+/g, '-').toLowerCase()}`;
}

function multipleIndices(name, breed, cellDOMRef, cellRef) {
  return `name ${name.toLowerCase()}`;
}