[Docs] Register Custom Filter Method

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<html>

<head>
  <meta charset="utf-8">
  <title>ZingGrid: Docs Getting Started</title>
  <!--Script Reference[1]-->
  <script nonce="undefined" src="https://cdn.zinggrid.com/zinggrid.min.js"></script>
  <style>
    html,
    body {
      height: 100%;
      width: 100%;
      margin: 0;
      padding: 0;
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    zing-grid[loading] {
      height: 277px;
    }
  </style>
</head>

<body>
  <zing-grid caption="Register Custom Filter Method" filter filter-conditions="customCondition, break, default">
    <zg-data data='[
        { "first": "Maria", "last": "John", "number": 123 },
        { "first": "David", "last": "Smith", "number": 456 },
        { "first": "Felicity", "last": "Snow", "number": 789 }
      ]'></zg-data>
  </zing-grid>
  <script>
    ZingGrid.setLicense(['26ccbfec16b8be9ee98c7d57bee6e498']);
    let customCondition = {
      title: "Starts With M",
      fieldCount: 0,
      filterMethod: (oConfig) => {
        return oConfig.dataVal.indexOf('M') === 0;
      }
    };
    ZingGrid.registerCustomFilterMethod('customCondition', customCondition);
  </script>
</body>

</html>

<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <title>ZingGrid: Docs Getting Started</title>
  <!--Script Reference[1]-->
  <script src="https://cdn.zinggrid.com/zinggrid.min.js"></script>
</head>

<body>
  <zing-grid caption="Register Custom Filter Method" filter filter-conditions="customCondition, break, default">
    <zg-data data='[
        { "first": "Maria", "last": "John", "number": 123 },
        { "first": "David", "last": "Smith", "number": 456 },
        { "first": "Felicity", "last": "Snow", "number": 789 }
      ]'></zg-data>
  </zing-grid>
</body>

</html>

html,
body {
  height: 100%;
  width: 100%;
  margin: 0;
  padding: 0;
}

let customCondition = {
  title: "Starts With M",
  fieldCount: 0,
  filterMethod: (oConfig) => {
    return oConfig.dataVal.indexOf('M') === 0;
  }
};
ZingGrid.registerCustomFilterMethod('customCondition', customCondition);