# vw_to_vega works

    Code
      vw_as_json(vw_to_vega(spec_mtcars))
    Output
      {
        "$schema": "https://vega.github.io/schema/vega/v5.json",
        "description": "An mtcars example.",
        "background": "white",
        "padding": 5,
        "width": 300,
        "height": 300,
        "style": "cell",
        "data": [
          {
            "name": "source_0",
            "values": [
              {
                "mpg": 21,
                "cyl": 6,
                "disp": 160,
                "hp": 110,
                "drat": 3.9,
                "wt": 2.62,
                "qsec": 16.46,
                "vs": 0,
                "am": 1,
                "gear": 4,
                "carb": 4,
                "_row": "Mazda RX4"
              },
              {
                "mpg": 21,
                "cyl": 6,
                "disp": 160,
                "hp": 110,
                "drat": 3.9,
                "wt": 2.875,
                "qsec": 17.02,
                "vs": 0,
                "am": 1,
                "gear": 4,
                "carb": 4,
                "_row": "Mazda RX4 Wag"
              },
              {
                "mpg": 22.8,
                "cyl": 4,
                "disp": 108,
                "hp": 93,
                "drat": 3.85,
                "wt": 2.32,
                "qsec": 18.61,
                "vs": 1,
                "am": 1,
                "gear": 4,
                "carb": 1,
                "_row": "Datsun 710"
              },
              {
                "mpg": 21.4,
                "cyl": 6,
                "disp": 258,
                "hp": 110,
                "drat": 3.08,
                "wt": 3.215,
                "qsec": 19.44,
                "vs": 1,
                "am": 0,
                "gear": 3,
                "carb": 1,
                "_row": "Hornet 4 Drive"
              },
              {
                "mpg": 18.7,
                "cyl": 8,
                "disp": 360,
                "hp": 175,
                "drat": 3.15,
                "wt": 3.44,
                "qsec": 17.02,
                "vs": 0,
                "am": 0,
                "gear": 3,
                "carb": 2,
                "_row": "Hornet Sportabout"
              },
              {
                "mpg": 18.1,
                "cyl": 6,
                "disp": 225,
                "hp": 105,
                "drat": 2.76,
                "wt": 3.46,
                "qsec": 20.22,
                "vs": 1,
                "am": 0,
                "gear": 3,
                "carb": 1,
                "_row": "Valiant"
              },
              {
                "mpg": 14.3,
                "cyl": 8,
                "disp": 360,
                "hp": 245,
                "drat": 3.21,
                "wt": 3.57,
                "qsec": 15.84,
                "vs": 0,
                "am": 0,
                "gear": 3,
                "carb": 4,
                "_row": "Duster 360"
              },
              {
                "mpg": 24.4,
                "cyl": 4,
                "disp": 146.7,
                "hp": 62,
                "drat": 3.69,
                "wt": 3.19,
                "qsec": 20,
                "vs": 1,
                "am": 0,
                "gear": 4,
                "carb": 2,
                "_row": "Merc 240D"
              },
              {
                "mpg": 22.8,
                "cyl": 4,
                "disp": 140.8,
                "hp": 95,
                "drat": 3.92,
                "wt": 3.15,
                "qsec": 22.9,
                "vs": 1,
                "am": 0,
                "gear": 4,
                "carb": 2,
                "_row": "Merc 230"
              },
              {
                "mpg": 19.2,
                "cyl": 6,
                "disp": 167.6,
                "hp": 123,
                "drat": 3.92,
                "wt": 3.44,
                "qsec": 18.3,
                "vs": 1,
                "am": 0,
                "gear": 4,
                "carb": 4,
                "_row": "Merc 280"
              },
              {
                "mpg": 17.8,
                "cyl": 6,
                "disp": 167.6,
                "hp": 123,
                "drat": 3.92,
                "wt": 3.44,
                "qsec": 18.9,
                "vs": 1,
                "am": 0,
                "gear": 4,
                "carb": 4,
                "_row": "Merc 280C"
              },
              {
                "mpg": 16.4,
                "cyl": 8,
                "disp": 275.8,
                "hp": 180,
                "drat": 3.07,
                "wt": 4.07,
                "qsec": 17.4,
                "vs": 0,
                "am": 0,
                "gear": 3,
                "carb": 3,
                "_row": "Merc 450SE"
              },
              {
                "mpg": 17.3,
                "cyl": 8,
                "disp": 275.8,
                "hp": 180,
                "drat": 3.07,
                "wt": 3.73,
                "qsec": 17.6,
                "vs": 0,
                "am": 0,
                "gear": 3,
                "carb": 3,
                "_row": "Merc 450SL"
              },
              {
                "mpg": 15.2,
                "cyl": 8,
                "disp": 275.8,
                "hp": 180,
                "drat": 3.07,
                "wt": 3.78,
                "qsec": 18,
                "vs": 0,
                "am": 0,
                "gear": 3,
                "carb": 3,
                "_row": "Merc 450SLC"
              },
              {
                "mpg": 10.4,
                "cyl": 8,
                "disp": 472,
                "hp": 205,
                "drat": 2.93,
                "wt": 5.25,
                "qsec": 17.98,
                "vs": 0,
                "am": 0,
                "gear": 3,
                "carb": 4,
                "_row": "Cadillac Fleetwood"
              },
              {
                "mpg": 10.4,
                "cyl": 8,
                "disp": 460,
                "hp": 215,
                "drat": 3,
                "wt": 5.424,
                "qsec": 17.82,
                "vs": 0,
                "am": 0,
                "gear": 3,
                "carb": 4,
                "_row": "Lincoln Continental"
              },
              {
                "mpg": 14.7,
                "cyl": 8,
                "disp": 440,
                "hp": 230,
                "drat": 3.23,
                "wt": 5.345,
                "qsec": 17.42,
                "vs": 0,
                "am": 0,
                "gear": 3,
                "carb": 4,
                "_row": "Chrysler Imperial"
              },
              {
                "mpg": 32.4,
                "cyl": 4,
                "disp": 78.7,
                "hp": 66,
                "drat": 4.08,
                "wt": 2.2,
                "qsec": 19.47,
                "vs": 1,
                "am": 1,
                "gear": 4,
                "carb": 1,
                "_row": "Fiat 128"
              },
              {
                "mpg": 30.4,
                "cyl": 4,
                "disp": 75.7,
                "hp": 52,
                "drat": 4.93,
                "wt": 1.615,
                "qsec": 18.52,
                "vs": 1,
                "am": 1,
                "gear": 4,
                "carb": 2,
                "_row": "Honda Civic"
              },
              {
                "mpg": 33.9,
                "cyl": 4,
                "disp": 71.1,
                "hp": 65,
                "drat": 4.22,
                "wt": 1.835,
                "qsec": 19.9,
                "vs": 1,
                "am": 1,
                "gear": 4,
                "carb": 1,
                "_row": "Toyota Corolla"
              },
              {
                "mpg": 21.5,
                "cyl": 4,
                "disp": 120.1,
                "hp": 97,
                "drat": 3.7,
                "wt": 2.465,
                "qsec": 20.01,
                "vs": 1,
                "am": 0,
                "gear": 3,
                "carb": 1,
                "_row": "Toyota Corona"
              },
              {
                "mpg": 15.5,
                "cyl": 8,
                "disp": 318,
                "hp": 150,
                "drat": 2.76,
                "wt": 3.52,
                "qsec": 16.87,
                "vs": 0,
                "am": 0,
                "gear": 3,
                "carb": 2,
                "_row": "Dodge Challenger"
              },
              {
                "mpg": 15.2,
                "cyl": 8,
                "disp": 304,
                "hp": 150,
                "drat": 3.15,
                "wt": 3.435,
                "qsec": 17.3,
                "vs": 0,
                "am": 0,
                "gear": 3,
                "carb": 2,
                "_row": "AMC Javelin"
              },
              {
                "mpg": 13.3,
                "cyl": 8,
                "disp": 350,
                "hp": 245,
                "drat": 3.73,
                "wt": 3.84,
                "qsec": 15.41,
                "vs": 0,
                "am": 0,
                "gear": 3,
                "carb": 4,
                "_row": "Camaro Z28"
              },
              {
                "mpg": 19.2,
                "cyl": 8,
                "disp": 400,
                "hp": 175,
                "drat": 3.08,
                "wt": 3.845,
                "qsec": 17.05,
                "vs": 0,
                "am": 0,
                "gear": 3,
                "carb": 2,
                "_row": "Pontiac Firebird"
              },
              {
                "mpg": 27.3,
                "cyl": 4,
                "disp": 79,
                "hp": 66,
                "drat": 4.08,
                "wt": 1.935,
                "qsec": 18.9,
                "vs": 1,
                "am": 1,
                "gear": 4,
                "carb": 1,
                "_row": "Fiat X1-9"
              },
              {
                "mpg": 26,
                "cyl": 4,
                "disp": 120.3,
                "hp": 91,
                "drat": 4.43,
                "wt": 2.14,
                "qsec": 16.7,
                "vs": 0,
                "am": 1,
                "gear": 5,
                "carb": 2,
                "_row": "Porsche 914-2"
              },
              {
                "mpg": 30.4,
                "cyl": 4,
                "disp": 95.1,
                "hp": 113,
                "drat": 3.77,
                "wt": 1.513,
                "qsec": 16.9,
                "vs": 1,
                "am": 1,
                "gear": 5,
                "carb": 2,
                "_row": "Lotus Europa"
              },
              {
                "mpg": 15.8,
                "cyl": 8,
                "disp": 351,
                "hp": 264,
                "drat": 4.22,
                "wt": 3.17,
                "qsec": 14.5,
                "vs": 0,
                "am": 1,
                "gear": 5,
                "carb": 4,
                "_row": "Ford Pantera L"
              },
              {
                "mpg": 19.7,
                "cyl": 6,
                "disp": 145,
                "hp": 175,
                "drat": 3.62,
                "wt": 2.77,
                "qsec": 15.5,
                "vs": 0,
                "am": 1,
                "gear": 5,
                "carb": 6,
                "_row": "Ferrari Dino"
              },
              {
                "mpg": 15,
                "cyl": 8,
                "disp": 301,
                "hp": 335,
                "drat": 3.54,
                "wt": 3.57,
                "qsec": 14.6,
                "vs": 0,
                "am": 1,
                "gear": 5,
                "carb": 8,
                "_row": "Maserati Bora"
              },
              {
                "mpg": 21.4,
                "cyl": 4,
                "disp": 121,
                "hp": 109,
                "drat": 4.11,
                "wt": 2.78,
                "qsec": 18.6,
                "vs": 1,
                "am": 1,
                "gear": 4,
                "carb": 2,
                "_row": "Volvo 142E"
              }
            ]
          },
          {
            "name": "data_0",
            "source": "source_0",
            "transform": [
              {
                "type": "filter",
                "expr": "isValid(datum[\"wt\"]) && isFinite(+datum[\"wt\"]) && isValid(datum[\"mpg\"]) && isFinite(+datum[\"mpg\"])"
              }
            ]
          }
        ],
        "marks": [
          {
            "name": "marks",
            "type": "symbol",
            "style": [
              "point"
            ],
            "from": {
              "data": "data_0"
            },
            "encode": {
              "update": {
                "opacity": {
                  "value": 0.7
                },
                "fill": {
                  "value": "transparent"
                },
                "stroke": {
                  "scale": "color",
                  "field": "cyl"
                },
                "ariaRoleDescription": {
                  "value": "point"
                },
                "description": {
                  "signal": "\"wt: \" + (format(datum[\"wt\"], \"\")) + \"; mpg: \" + (format(datum[\"mpg\"], \"\")) + \"; cyl: \" + (isValid(datum[\"cyl\"]) ? datum[\"cyl\"] : \"\"+datum[\"cyl\"])"
                },
                "x": {
                  "scale": "x",
                  "field": "wt"
                },
                "y": {
                  "scale": "y",
                  "field": "mpg"
                }
              }
            }
          }
        ],
        "scales": [
          {
            "name": "x",
            "type": "linear",
            "domain": {
              "data": "data_0",
              "field": "wt"
            },
            "range": [
              0,
              {
                "signal": "width"
              }
            ],
            "nice": true,
            "zero": true
          },
          {
            "name": "y",
            "type": "linear",
            "domain": {
              "data": "data_0",
              "field": "mpg"
            },
            "range": [
              {
                "signal": "height"
              },
              0
            ],
            "nice": true,
            "zero": true
          },
          {
            "name": "color",
            "type": "ordinal",
            "domain": {
              "data": "data_0",
              "field": "cyl",
              "sort": true
            },
            "range": "category"
          }
        ],
        "axes": [
          {
            "scale": "x",
            "orient": "bottom",
            "gridScale": "y",
            "grid": true,
            "tickCount": {
              "signal": "ceil(width/40)"
            },
            "domain": false,
            "labels": false,
            "aria": false,
            "maxExtent": 0,
            "minExtent": 0,
            "ticks": false,
            "zindex": 0
          },
          {
            "scale": "y",
            "orient": "left",
            "gridScale": "x",
            "grid": true,
            "tickCount": {
              "signal": "ceil(height/40)"
            },
            "domain": false,
            "labels": false,
            "aria": false,
            "maxExtent": 0,
            "minExtent": 0,
            "ticks": false,
            "zindex": 0
          },
          {
            "scale": "x",
            "orient": "bottom",
            "grid": false,
            "title": "wt",
            "labelFlush": true,
            "labelOverlap": true,
            "tickCount": {
              "signal": "ceil(width/40)"
            },
            "zindex": 0
          },
          {
            "scale": "y",
            "orient": "left",
            "grid": false,
            "title": "mpg",
            "labelOverlap": true,
            "tickCount": {
              "signal": "ceil(height/40)"
            },
            "zindex": 0
          }
        ],
        "legends": [
          {
            "stroke": "color",
            "symbolType": "circle",
            "title": "cyl",
            "encode": {
              "symbols": {
                "update": {
                  "fill": {
                    "value": "transparent"
                  },
                  "opacity": {
                    "value": 0.7
                  }
                }
              }
            }
          }
        ]
      } 

---

    Code
      vw_as_json(vw_to_vega(spec_mtcars4))
    Output
      {
        "$schema": "https://vega.github.io/schema/vega/v5.json",
        "description": "An mtcars example.",
        "background": "white",
        "padding": 5,
        "width": 300,
        "height": 300,
        "style": "cell",
        "data": [
          {
            "name": "source_0",
            "values": [
              {
                "mpg": 21,
                "cyl": 6,
                "disp": 160,
                "hp": 110,
                "drat": 3.9,
                "wt": 2.62,
                "qsec": 16.46,
                "vs": 0,
                "am": 1,
                "gear": 4,
                "carb": 4,
                "_row": "Mazda RX4"
              },
              {
                "mpg": 21,
                "cyl": 6,
                "disp": 160,
                "hp": 110,
                "drat": 3.9,
                "wt": 2.875,
                "qsec": 17.02,
                "vs": 0,
                "am": 1,
                "gear": 4,
                "carb": 4,
                "_row": "Mazda RX4 Wag"
              },
              {
                "mpg": 22.8,
                "cyl": 4,
                "disp": 108,
                "hp": 93,
                "drat": 3.85,
                "wt": 2.32,
                "qsec": 18.61,
                "vs": 1,
                "am": 1,
                "gear": 4,
                "carb": 1,
                "_row": "Datsun 710"
              },
              {
                "mpg": 21.4,
                "cyl": 6,
                "disp": 258,
                "hp": 110,
                "drat": 3.08,
                "wt": 3.215,
                "qsec": 19.44,
                "vs": 1,
                "am": 0,
                "gear": 3,
                "carb": 1,
                "_row": "Hornet 4 Drive"
              },
              {
                "mpg": 18.7,
                "cyl": 8,
                "disp": 360,
                "hp": 175,
                "drat": 3.15,
                "wt": 3.44,
                "qsec": 17.02,
                "vs": 0,
                "am": 0,
                "gear": 3,
                "carb": 2,
                "_row": "Hornet Sportabout"
              },
              {
                "mpg": 18.1,
                "cyl": 6,
                "disp": 225,
                "hp": 105,
                "drat": 2.76,
                "wt": 3.46,
                "qsec": 20.22,
                "vs": 1,
                "am": 0,
                "gear": 3,
                "carb": 1,
                "_row": "Valiant"
              },
              {
                "mpg": 14.3,
                "cyl": 8,
                "disp": 360,
                "hp": 245,
                "drat": 3.21,
                "wt": 3.57,
                "qsec": 15.84,
                "vs": 0,
                "am": 0,
                "gear": 3,
                "carb": 4,
                "_row": "Duster 360"
              },
              {
                "mpg": 24.4,
                "cyl": 4,
                "disp": 146.7,
                "hp": 62,
                "drat": 3.69,
                "wt": 3.19,
                "qsec": 20,
                "vs": 1,
                "am": 0,
                "gear": 4,
                "carb": 2,
                "_row": "Merc 240D"
              },
              {
                "mpg": 22.8,
                "cyl": 4,
                "disp": 140.8,
                "hp": 95,
                "drat": 3.92,
                "wt": 3.15,
                "qsec": 22.9,
                "vs": 1,
                "am": 0,
                "gear": 4,
                "carb": 2,
                "_row": "Merc 230"
              },
              {
                "mpg": 19.2,
                "cyl": 6,
                "disp": 167.6,
                "hp": 123,
                "drat": 3.92,
                "wt": 3.44,
                "qsec": 18.3,
                "vs": 1,
                "am": 0,
                "gear": 4,
                "carb": 4,
                "_row": "Merc 280"
              },
              {
                "mpg": 17.8,
                "cyl": 6,
                "disp": 167.6,
                "hp": 123,
                "drat": 3.92,
                "wt": 3.44,
                "qsec": 18.9,
                "vs": 1,
                "am": 0,
                "gear": 4,
                "carb": 4,
                "_row": "Merc 280C"
              },
              {
                "mpg": 16.4,
                "cyl": 8,
                "disp": 275.8,
                "hp": 180,
                "drat": 3.07,
                "wt": 4.07,
                "qsec": 17.4,
                "vs": 0,
                "am": 0,
                "gear": 3,
                "carb": 3,
                "_row": "Merc 450SE"
              },
              {
                "mpg": 17.3,
                "cyl": 8,
                "disp": 275.8,
                "hp": 180,
                "drat": 3.07,
                "wt": 3.73,
                "qsec": 17.6,
                "vs": 0,
                "am": 0,
                "gear": 3,
                "carb": 3,
                "_row": "Merc 450SL"
              },
              {
                "mpg": 15.2,
                "cyl": 8,
                "disp": 275.8,
                "hp": 180,
                "drat": 3.07,
                "wt": 3.78,
                "qsec": 18,
                "vs": 0,
                "am": 0,
                "gear": 3,
                "carb": 3,
                "_row": "Merc 450SLC"
              },
              {
                "mpg": 10.4,
                "cyl": 8,
                "disp": 472,
                "hp": 205,
                "drat": 2.93,
                "wt": 5.25,
                "qsec": 17.98,
                "vs": 0,
                "am": 0,
                "gear": 3,
                "carb": 4,
                "_row": "Cadillac Fleetwood"
              },
              {
                "mpg": 10.4,
                "cyl": 8,
                "disp": 460,
                "hp": 215,
                "drat": 3,
                "wt": 5.424,
                "qsec": 17.82,
                "vs": 0,
                "am": 0,
                "gear": 3,
                "carb": 4,
                "_row": "Lincoln Continental"
              },
              {
                "mpg": 14.7,
                "cyl": 8,
                "disp": 440,
                "hp": 230,
                "drat": 3.23,
                "wt": 5.345,
                "qsec": 17.42,
                "vs": 0,
                "am": 0,
                "gear": 3,
                "carb": 4,
                "_row": "Chrysler Imperial"
              },
              {
                "mpg": 32.4,
                "cyl": 4,
                "disp": 78.7,
                "hp": 66,
                "drat": 4.08,
                "wt": 2.2,
                "qsec": 19.47,
                "vs": 1,
                "am": 1,
                "gear": 4,
                "carb": 1,
                "_row": "Fiat 128"
              },
              {
                "mpg": 30.4,
                "cyl": 4,
                "disp": 75.7,
                "hp": 52,
                "drat": 4.93,
                "wt": 1.615,
                "qsec": 18.52,
                "vs": 1,
                "am": 1,
                "gear": 4,
                "carb": 2,
                "_row": "Honda Civic"
              },
              {
                "mpg": 33.9,
                "cyl": 4,
                "disp": 71.1,
                "hp": 65,
                "drat": 4.22,
                "wt": 1.835,
                "qsec": 19.9,
                "vs": 1,
                "am": 1,
                "gear": 4,
                "carb": 1,
                "_row": "Toyota Corolla"
              },
              {
                "mpg": 21.5,
                "cyl": 4,
                "disp": 120.1,
                "hp": 97,
                "drat": 3.7,
                "wt": 2.465,
                "qsec": 20.01,
                "vs": 1,
                "am": 0,
                "gear": 3,
                "carb": 1,
                "_row": "Toyota Corona"
              },
              {
                "mpg": 15.5,
                "cyl": 8,
                "disp": 318,
                "hp": 150,
                "drat": 2.76,
                "wt": 3.52,
                "qsec": 16.87,
                "vs": 0,
                "am": 0,
                "gear": 3,
                "carb": 2,
                "_row": "Dodge Challenger"
              },
              {
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              },
              {
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              },
              {
                "mpg": 27.3,
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              },
              {
                "mpg": 26,
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              },
              {
                "mpg": 30.4,
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              {
                "mpg": 15.8,
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                "mpg": 15,
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                "type": "filter",
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