Demo of config override bug

forked from domoritz's block: Vega block example

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://cdnjs.cloudflare.com/ajax/libs/vega/3.0.0-beta.33/vega.js"></script>
  <style>
    body {
      font-family: sans-serif;
    }
    
    .vega-actions a {
      padding: 0.2em;
    }
  </style>
</head>

<body>  
  <div id="vis"></div>
  
  <script>
    var spec = {
      "$schema": "https://vega.github.io/schema/vega/v3.0.json",
      "width": 400,
      "height": 200,
      "padding": 5,

"data": [
        {
          "name": "table",
          "values": [
            {"category": "A", "amount": 28},
            {"category": "B", "amount": 55},
            {"category": "C", "amount": 43},
            {"category": "D", "amount": 91},
            {"category": "E", "amount": 81},
            {"category": "F", "amount": 53},
            {"category": "G", "amount": 19},
            {"category": "H", "amount": 87}
          ]
        }
      ],

"signals": [
        {
          "name": "tooltip",
          "value": {},
          "on": [
            {"events": "rect:mouseover", "update": "datum"},
            {"events": "rect:mouseout",  "update": "{}"}
          ]
        }
      ],

"scales": [
        {
          "name": "xscale",
          "type": "band",
          "domain": {"data": "table", "field": "category"},
          "range": "width"
        },
        {
          "name": "yscale",
          "domain": {"data": "table", "field": "amount"},
          "nice": true,
          "range": "height"
        }
      ],

"axes": [
        { "orient": "bottom", "scale": "xscale" },
        { "orient": "left", "scale": "yscale" }
      ],

"marks": [
        {
          "type": "rect",
          "from": {"data":"table"},
          "encode": {
            "enter": {
              "x": {"scale": "xscale", "field": "category", "offset": 1},
              "width": {"scale": "xscale", "band": 1, "offset": -1},
              "y": {"scale": "yscale", "field": "amount"},
              "y2": {"scale": "yscale", "value": 0}
            },
            "update": {
              "fill": {"value": "steelblue"}
            },
            "hover": {
              "fill": {"value": "red"}
            }
          }
        },
        {
          "type": "text",
          "encode": {
            "enter": {
              "align": {"value": "center"},
              "baseline": {"value": "bottom"},
              "fill": {"value": "#333"}
            },
            "update": {
              "x": {"scale": "xscale", "signal": "tooltip.category", "band": 0.5},
              "y": {"scale": "yscale", "signal": "tooltip.amount", "offset": -2},
              "text": {"signal": "tooltip.amount"},
              "fillOpacity": [
                {"test": "datum === tooltip", "value": 0},
                {"value": 1}
              ]
            }
          }
        }
      ],
      "config": {
        "axis": {
          "labelFont": "serif",
          "labelFontSize": 16,
          "tickWidth": 3,
          "tickColor": "red"
        }
      }
    }
 
    var runtime = vega.parse(spec, {});
    
    var view = new vega.View(runtime)
      .logLevel(vega.Warn) // set view logging level
      .initialize(document.querySelector('#vis')) // set parent DOM element
      .renderer('svg') // set render type (defaults to 'canvas')
      .hover() // enable hover event processing
      .run(); // update and render the view
  </script>
</body>

https://cdnjs.cloudflare.com/ajax/libs/vega/3.0.0-beta.33/vega.js