headerlabels.vl

{
    "transform": [
        {
            "filter": "datum.year === 2000"
        },
        {
            "as": "gender",
            "calculate": "datum.sex === 2 ? 'Female' : 'Male'"
        }
    ],
    "config": {
        "header": {
            "labels": false
        }
    },
    "mark": "bar",
    "data": {
        "url": "https://vega.github.io/vega-lite/data/population.json"
    },
    "$schema": "https://vega.github.io/schema/vega-lite/v4.json",
    "encoding": {
        "color": {
            "field": "gender",
            "type": "nominal"
        },
        "x": {
            "field": "age",
            "type": "ordinal"
        },
        "column": {
            "field": "gender",
            "type": "nominal"
        },
        "y": {
            "field": "people",
            "aggregate": "sum",
            "type": "quantitative"
        }
    }
}