Extending Deneb/Vega-Lite Toggle Switch from 2-State to 3-State (Working Day / Non-Working Day / All

Hi y5famfnatudu,

I hope you are doing well ☺️❤️

To implement a 3 state toggle switch in Deneb/Vega-Lite you need to use a parameter (signal) with a cyclic update expression. Here is a couple of Approaches:

First Approach: Complete Deneb/Vega-Lite Specification

{
  "$schema": "https://vega.github.io/schema/vega-lite/v5.json",
  "params": [
    {
      "name": "filterToggle",
      "value": 0,
      "bind": {
        "input": "radio",
        "options": [0, 1, 2],
        "labels": ["Working Days (1)", "Non-Working Days (0)", "All Records"]
      }
    }
  ],
  "data": {"name": "dataset"},
  "transform": [
    {
      "filter": {
        "condition": {
          "param": "filterToggle",
          "value": 2,
          "empty": false
        },
        "value": {
          "field": "IsWorkingDay",
          "equal": {
            "signal": "filterToggle == 0 ? 1 : 0"
          }
        }
      }
    },
    {
      "calculate": "datum.IsWorkingDay == 1 ? 'Working Day' : 'Non-Working Day'",
      "as": "Day_Type"
    }
  ],
  "mark": "bar",  // or your preferred mark type
  "encoding": {
    // Your encoding here
    "x": {"field": "SomeField", "type": "nominal"},
    "y": {"aggregate": "count", "type": "quantitative"},
    "color": {"field": "Day_Type", "type": "nominal"}
  }
}

Alternative Approach: ClickCycling Button 

• If you want a single button that cycles through states on each click:

{
  "$schema": "https://vega.github.io/schema/vega-lite/v5.json",
  "data": {"name": "dataset"},
  "signals": [
    {
      "name": "toggleState",
      "value": 0,
      "on": [
        {
          "events": {"type": "click", "markname": "toggleButton"},
          "update": "(toggleState + 1) % 3"
        }
      ]
    }
  ],
  "marks": [
    {
      "type": "rect",
      "name": "toggleButton",
      "encode": {
        "enter": {
          "x": {"value": 0},
          "y": {"value": 0},
          "width": {"value": 120},
          "height": {"value": 30},
          "fill": {"value": "lightgray"},
          "cornerRadius": {"value": 15}
        },
        "update": {
          "fill": {
            "signal": "toggleState == 0 ? '#4CAF50' : toggleState == 1 ? '#F44336' : '#2196F3'"
          }
        }
      }
    },
    {
      "type": "text",
      "name": "toggleLabel",
      "encode": {
        "enter": {
          "x": {"value": 60},
          "y": {"value": 18},
          "align": {"value": "center"},
          "baseline": {"value": "middle"},
          "fontSize": {"value": 12},
          "fill": {"value": "white"}
        },
        "update": {
          "text": {
            "signal": "toggleState == 0 ? 'Working Days' : toggleState == 1 ? 'Non-Working Days' : 'All Days'"
          }
        }
      }
    }
  ],
  "transform": [
    {
      "filter": {
        "condition": {"signal": "toggleState == 2"},
        "value": {
          "field": "IsWorkingDay",
          "equal": {"signal": "toggleState == 0 ? 1 : 0"}
        }
      }
    }
  ],
  "layer": [
    // Your visualization layers here
    {
      "mark": "bar",
      "encoding": {
        "x": {"field": "SomeField", "type": "nominal"},
        "y": {"aggregate": "count", "type": "quantitative"},
        "color": {
          "field": "IsWorkingDay",
          "type": "nominal",
          "scale": {
            "domain": [0, 1],
            "range": ["#F44336", "#4CAF50"]
          },
          "legend": {
            "title": "Day Type",
            "labelExpr": "datum.value == 1 ? 'Working Day' : 'Non-Working Day'"
          }
        }
      }
    }
  ]
}

Bonus Approach: Simple Radio Button Version

• If you prefer a simpler radio button

{
  "params": [
    {
      "name": "dayFilter",
      "value": 2,
      "bind": {
        "input": "select",
        "options": [0, 1, 2],
        "labels": ["Working Days Only", "Non-Working Days Only", "All Days"],
        "name": "Filter: "
      }
    }
  ],
  "transform": [
    {
      "filter": {
        "condition": {"param": "dayFilter", "value": 2},
        "value": {"field": "IsWorkingDay", "equal": {"param": "dayFilter"}}
      }
    }
  ]
}

Choose the Approach that best fits your visualization needs. The first approach with a cycling button is more interactive while the radio/select approaches are more explicit for users