RTP Popup Arcade Expression Example

arcade.js

// This is because the webmap can't parse our code for the fields that we are
// using since they are buried in field info dictionaries.
// This could be optimized to include only the fields that you use below
Expects($feature, '*');

// I can't believe that arcade doesn't define an expression like this!
function concat(target, source) {
  for (var i in source) {
    Push(target, source[i]);
  }
}

var commonFields = [
  {
    fieldName: 'begin_place',
    label: 'From',
  },
  {
    fieldName: 'end_place',
    label: 'End',
  },
  {
    fieldName: 'mode',
    label: 'Mode',
  },
];

if ($feature.mode == 'Highway') {
  var highwayFields = [
    {
      fieldName: 'current_lanesTEXT',
      label: 'Current Lanes',
    },
    {
      fieldName: 'region',
      label: 'UDOT Region',
    },
  ];

  concat(commonFields, highwayFields);
}

var additionalFields = [
  {
    fieldName: 'route_name',
    label: 'Route Name',
  },
];

concat(commonFields, additionalFields);

// just so that we can see what fields are available...
Console($feature);

return {
  type: 'fields',
  fieldInfos: commonFields,
};

You can see this expression in action in the popup config for the "Lines Displayed by Mode" layer in this webmap.