ExpressionContent

// Creates an column chart where each category/value
// is an aggregate of two or more fields
layer.popupTemplate = {
  title: "Educational Attainment",
  content: [{
    type: "expression",
    expressionInfo: {
      expression: `
        // Create a dictionary of attributes representing the values
        // to display in the chart
        var attributes = {
          "No School": $feature.no_school + $feature.some_primary,
          "Primary": $feature.primary_complete + $feature.some_secondary,
          "Secondary": $feature.secondary_complete + $feature.some_highSchool,
          "High School": $feature.highSchool_diploma + $feature.highSchool_ged + $feature.some_college,
          "College/University": $feature.associates + $feature.bachelors + $feature.masters + $feature.doctorate + $feature.professional;
        };

        var fields = [];

        // Create an array representing the attribute names (or keys)
        for (var k in attributes){
          Push(fields, k);
        }

        // Returns a dictionary providing the information
        // required by the popup to render a column chart
        return {
          type: "media",
          attributes: attributes,
          title: "Educational attainment",
          mediaInfos: [{
            type: "columnchart",
            value: {
              // The list of attribute names (keys) to include in the chart
              fields: fields
            }
          }]
        };
      `,
      title: "Educational Attainment"
    }
  }]
};