Arcade 表达式

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// returns the % of the population that is age 18 and older
renderer.valueExpression = "Round( ($feature.AGE_18UP / $feature.TOTAL_POP) * 100 )"; 

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renderer.valueExpression = `
  var republican = $feature.MP06025a_B;
  var democrat = $feature.MP06024a_B;
  var independent = $feature.MP06026a_B;

  var parties = [ republican, democrat, independent ];
  var total = Sum(parties);
  var max = Max(parties);
  return (max / total) * 100;
`; 

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layer.popupTemplate = {
  content: "{expression/percent-unemployed}",
  expressionInfos: [
    {
      name: "percent-unemployed",
      title: "Percent unemployed",
      expression: `
        var unemploymentRate = ( $feature.UNEMP_CY / $feature.LABOR_FORCE ) * 100;
        var population = $feature.POP_16UP;
        var populationNotWorking = ( ( $feature.UNEMP_CY + $feature.NOT_LABORFORCE_16 ) / $feature.POP_16UP ) * 100;

        // returns a string built using an Arcade template literal

        return \`\${$feature.COUNTY} County

        - Unemployment rate: \${Text(unemploymentRate, "##.#")}%
        - % population not working: \${Text(populationNotWorking, "##.#")}%
        - Population: \${Text(population, "#,###")}\`
      `
    }
  ]
} 

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<script type="text/plain" id="adult-population">
  var republican = $feature.MP06025a_B;
  var democrat = $feature.MP06024a_B;
  var independent = $feature.MP06026a_B;

  var parties = [ republican, democrat, independent ];
  var total = Sum(parties);
  var max = Max(parties);
  return (max / total) * 100;
</script> 

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renderer.valueExpression = document.getElementById("adult-population").text; 

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// returns the value of a field in the layer
// the value of this field will be the label for each feature
const arcade = "$feature.STATION_NAME";

// this object autocasts as new LabelClass()
const labelClass = {
  // set the arcade expression to the `expression` property of labelExpressionInfo
  labelExpressionInfo: {
    expression: arcade
  },
  labelPlacement: "below-right",
  minScale: 2500000,
  symbol: {
    type: "label-3d",
    symbolLayers: [{
      type: "text",
      material: { color: "white" },
      halo: {
        color: "black",
        size: 1
      },
      size: 8
    }]
  }
};

// set the label class to the feature layer
featureLayer.labelingInfo = [ labelClass ]; 

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<script type="text/plain" id="wind-direction">
  var DEG = $feature.WIND_DIRECT;
  var SPEED = $feature.WIND_SPEED;
  var DIR = When( SPEED == 0, '',
    (DEG < 22.5 && DEG >= 0) || DEG > 337.5, 'N',
     DEG >= 22.5 && DEG < 67.5, 'NE',
     DEG >= 67.5 && DEG < 112.5, 'E',
     DEG >= 112.5 && DEG < 157.5, 'SE',
     DEG >= 157.5 && DEG < 202.5, 'S',
     DEG >= 202.5 && DEG < 247.5, 'SW',
     DEG >= 247.5 && DEG < 292.5, 'W',
     DEG >= 292.5 && DEG < 337.5, 'NW', '' );
  var WIND = SPEED + ' mph ' + DIR;
  return WIND;
</script> 

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// labor force participation rate
Round(($feature.CIVLBFR_CY / $feature.POP_16UP)*100,2) 

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layer.popupTemplate = {
  expressionInfos: [{
    name: "participation-rate",
    title: "% of population 16+ participating in the labor force",
    expression: "Round(($feature.CIVLBFR_CY / $feature.POP_16UP)*100,2)"
  }],
  content: "In {NAME} county, {expression/participation-rate}% of the population"
    + " participates in the labor force."
}; 

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layer.popupTemplate = {
  expressionInfos: [{
    name: "participation-rate",
    title: "% of population 16+ participating in the labor force",
    expression: "Round(($feature.CIVLBFR_CY / $feature.POP_16UP)*100,2)"
  }],
  content: [{
    type: "fields",
    fieldInfos: [{
      fieldName: "expression/participation-rate"
    }, {
      fieldName: "CIVLBFR_CY",
      label: "Civilian labor force",
      format: {
        places: 0,
        digitSeparator: true
      }
    }, {
      fieldName: "POP_16UP",
      label: "Population 16+",
      format: {
        places: 0,
        digitSeparator: true
      }
    }]
  }]
}; 

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// returns the sum of the cost field for all features in the cluster
$feature.cluster_count * $feature.cluster_avg_cost 

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// returns the total number of car crashes
// that resulted in at least one fatality in a
// cluster representing motor vehicle accidents
Count(Filter($aggregatedFeatures, "FATALITIES > 0")) 

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layer.featureReduction = {
  type: "cluster",
  popupTemplate: {
    expressionInfos: [{
      name: "total-cost",
      title: "Total damages",
      expression: "Text($feature.cluster_count * $feature.cluster_avg_cost, '$#,###.##')"
    }, {
      name: "fatalities",
      title: "Crashes with fatalities",
      expression: `
        Expects($aggregatedFeatures, 'FATALITIES')
        Count(Filter($aggregatedFeatures, 'FATALITIES > 0'))
      `
    }],
    content: `
      This cluster represents {cluster_count} motor vehical accidents. {expression/fatalities} of these crashes
      had at least one fatality. These crashes resulted in {expression/total-cost} of damages.
    `
  }
}; 

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// Creates a table with only fields that contain data
var fields = Schema($feature).fields;
function getNames(field){
  return field.name;
}
function filterValidFields(fieldName){
  var invalidNames = ["objectid", "fid", "shape__area", "shape__length"];
  return !includes(invalidNames, lower(fieldName)) && !IsEmpty($feature[fieldName]) && !IsNan($feature[fieldName]);
}

var validFields = Filter(Map(fields, getNames), filterValidFields);
var attributes = {};
var fieldInfos = [];

for (var f in validFields){
  var fieldName = validFields[f];
  Push(fieldInfos, { fieldName: fieldName });
  // format numbers with digit separator and one decimal place
  var value = IIF(TypeOf($feature[fieldName] == "Number"), Text($feature[fieldName], "#,#.#"), $feature[fieldName]);
  attributes[fieldName] = value;
}

return {
  type: "fields",
  fieldInfos: fieldInfos,
  attributes: attributes
}; 

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// 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"
    }
  }]
}; 

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<script type="text/plain" id="winning-party">
  // Write the expression and reference the value
  // of each field with a meaningful variable name within
  // the expression. Then calculate the max number with
  // the Max() function and use Decode() to return a string
  // value representing the party whose field value matches
  // the max value.

  var republican = $feature.MP06025a_B;
  var democrat = $feature.MP06024a_B;
  var independent = $feature.MP06026a_B;
  var parties = [republican, democrat, independent];
  // Decode() and Max() are built-in Arcade functions
  return Decode( Max(parties),
    republican, 'republican',
    democrat, 'democrat',
    independent, 'independent',
    'n/a');
</script> 

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// Assign the expression to the `valueExpression` property and
// set up the unique value infos based on the decode values
// you set up in the expression.

const winnerArcade = document.getElementById("winning-party").text;

const renderer = new UniqueValueRenderer({
  valueExpression: winnerArcade,
  valueExpressionTitle: "Counties by dominant party among registered voters",
  uniqueValueInfos: [{
    value: "democrat",
    symbol: createSymbol("#00c3ff"),
    label: "Democrat"
  }, {
    value: "republican",
    symbol: createSymbol("#ff002e"),
    label: "Republican"
  }, {
    value: "independent",
    symbol: createSymbol("#faff00"),
    label: "Independent/non-affiliated"
  }]
}); 

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<script type="text/plain" id="strength">
  // Write the expression and reference the value
  // of each field with a meaningful variable name within
  // the expression. Then calculate the max number with
  // the Max() function and the total using Sum().
  // Calculate the share of the max population within the
  // county. This value will be between 33 - 100 and will
  // be used to determine the feature's opacity.
  // Note the value is explicitly returned; it could also
  // be implicitly returned like the previous example

  var republican = $feature.MP06025a_B;
  var democrat = $feature.MP06024a_B;
  var independent = $feature.MP06026a_B;
  var parties = [republican, democrat, independent];
  var total = Sum(parties);
  var max = Max(parties);

  return (max / total) * 100;
</script> 

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// Assign the expression to the `valueExpression` property and
// set up the unique value infos based on the decode values
// you set up in the expression.

const strengthArcade = document.getElementById("strength").text;

const opacityVV = {
  type: "opacity",
  valueExpression: strengthArcade,
  stops: [
    { value: 33, opacity: 0.1 },
    { value: 50, opacity: 1.0 }
  ]
};

// Add the visual variable to the renderer

renderer.visualVariables = [ opacityVV ]; 

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const formTemplate = new FormTemplate({
  title: "Inspector report",
  description: "Enter all relevant information below",
  elements: [
    new FieldElement({
      fieldName: "inspector",
      label: "Inspector name"
    }),
    new FieldElement({
      fieldName: "status",
      label: "Issue status"
    }),
    new FieldElement({
      fieldName: "resolution",
      label: "Resolution",
      // expression defined below
      visibilityExpression: "resolutionVisible"
    })
  ],
  expressionInfos: [{
    name: "resolutionVisible",
    title: "Resolution if status is completed",
    expression: "$feature.status == 'Completed' && !IsEmpty($feature.resolution)"
  }]
}); 

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const formTemplate = new FormTemplate({
  title: "Inspector report",
  description: "Enter all relevant information below",
  elements: [
    new FieldElement({
      fieldName: "Area",
      label: "Area (square meters)",
      // expression defined in expressionInfos
      valueExpression: "area"
    }),
    new FieldElement({
      fieldName: "InspectorFirst",
      label: "First Name"
    })
    new FieldElement({
      fieldName: "InspectorLast",
      label: "Last Name"
    })
    new FieldElement({
      fieldName: "FullName",
      label: "Full Name",
      // expression defined in expressionInfos
      valueExpression: "fullName"
    }),
  ],
  expressionInfos: [{
    name: "area",
    title: "Area (square meters)",
    expression: "Round(AreaGeodetic($feature, 'square-meters'), 2)"
  }, {
    name: "fullName",
    title: "Inspector full name",
    expression: `
      IIF(!IsEmpty($feature.InspectorFirst) && !IsEmpty($feature.InspectorLast)){
        return $feature.InspectorFirst + " " + $feature.InspectorLast;
      }
    `
  }]
}); 

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// Orders features by storm warning duration in descending order.
// Warnings with longer durations will be
// rendered on top of warnings with shorter durations.
layer.orderBy = [{
  valueExpression: "DateDiff($feature.Watch_End, $feature.Watch_Start, 'hours' )",
  order: "descending"
}]; 

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layer.elevationInfo = {
  mode: "absolute-height",
  featureExpressionInfo: {
    expression: "Geometry($feature).z + $feature.HEIGHT"
  },
  unit: "meters"
};