Conditional Highcharts Marker Symbol Using Javascript

Question

I swear I've seen this done before, but can't seem to find the answer.

When I spin up Highcharts, is there a way to have an inline statement determine the marker symbol.

For example:

Highcharts.stockChart(chartElementId, {
    title: {
        text: 'Foo chart'
    },
    series: [{
        name: 'Foo',
        data: ...,
        marker: { 
            enabled: true,
            symbol: this.x > 1 ? 'circle' : 'square'
        }
    }]
});

I've seen something similar done in post-processing (after the chart is rendered), but I was wondering if there's a way to do it in the middle of rendering.

Answer 1

You can hook to a function responsible for drawing points - and before it is called, update points according to a symbol callback defined in the options.

Wrapping drawPoints method:

const H = Highcharts;

H.wrap(H.Series.prototype, 'drawPoints', function(p) {
  const options = this.options;
  const symbolCallback = options.marker && options.marker.symbolCallback;
  const points = this.points;

  if (symbolCallback && points.length) {
    points.forEach(point => {
      const symbol = symbolCallback.call(point);
      if (symbol) {
        point.update({
          marker: {
            symbol: symbol
          }
        }, false)
      }
    })
  }

  p.call(this);
})

series config:

series: [{
  marker: {
    symbolCallback: function() {
      return this.x > 2 ? this.y > 150 ? 'circle' : 'triangle' : 'square';
    }
  },

Live example

http://jsfiddle.net/09mqttxn/

 var H = Highcharts; H.wrap(H.Series.prototype, 'drawPoints', function(p) { const options = this.options; const symbolCallback = options.marker && options.marker.symbolCallback; const points = this.points; if (symbolCallback && points.length) { points.forEach(point => { const symbol = symbolCallback.call(point); if (symbol) { point.update({ marker: { symbol: symbol } }, false) } }) } p.call(this); }) H.chart('container', { series: [{ marker: { symbolCallback: function() { return this.x > 2 ? this.y > 150 ? 'circle' : 'triangle' : 'square'; } }, data: [29.9, 71.5, 106.4, 129.2, 144.0, 176.0, 135.6, 148.5, 216.4, 194.1, 95.6, 54.4] }] }); 

 <script src="https://code.highcharts.com/highcharts.src.js"></script> <div id="container" style="height: 400px"></div> 

Answer 2

In that case series should have 'x'. The idea is to use self-reference in series object:

{   x:2,
    name: 'Tokyo',
    marker: {
        enabled: true
    },
    init : function(){
        this.marker.symbol = this.x > 1 ? 'circle' : 'square';
        return this;
    },
    data: ....            
}.init()

jsfiddle