Highchart tooltip show nearest point

Question

I have been trying to make highchart tooltip to show the nearest point incase the x-axis value aren\'t align in different series.

This is what I got so far

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Answer 1

Before insertion, check whether points array contains the current point in your refresh callback function.

// Add the closest point to the array
if(points.indexOf(current)==-1)
   points.push(current);    

Highcharts.wrap(Highcharts.Tooltip.prototype, 'refresh', function (proceed) {
    var args = arguments,
        points = args[1],
        point = points[0],
        chart = point.series.chart;
    
    // Loop over all the series of the chart
    Highcharts.each(chart.series, function(series) {
        // This one already exist
        if (series == point.series) return;
        
        var current,
            dist,
            distance = Number.MAX_VALUE;
        // Loop over all the points
        Highcharts.each(series.points, function(p) {
            // use the distance in X to determine the closest point
            dist = Math.abs(p.x - point.x);
            if (dist < distance) {
                distance = dist;
                current = p;
            }
        });
        
        // Add the closest point to the array
        if(points.indexOf(current)==-1)
           points.push(current);        
    });  
    
    proceed.apply(this, [].slice.call(args, 1));
});

$('#container').highcharts({
    tooltip: {
        shared: true
    },
    xAxis: {
        crosshair: {
            color: '#F70000'
        }
    },
    series: [{
        data: [{
            x: 0.0,
            y: 1
        }, {
            x: 1.0,
            y: 2
        }, {
            x: 2.0,
            y: 3
        }, {
            x: 3.0,
            y: 2
        }, {
            x: 4.0,
            y: 1
        }]
    }, {
        data: [{
            x: 0.2,
            y: 0
        }, {
            x: 1.2,
            y: 1
        }, {
            x: 2.2,
            y: 1
        }, {
            x: 3.2,
            y: 1
        }, {
            x: 4.2,
            y: 2
        }]
    }, {
        data: [{
            x: 0.2,
            y: 5
        }, {
            x: 1.2,
            y: 9
        }, {
            x: 2.2,
            y: 4
        }, {
            x: 3.2,
            y: 5
        }, {
            x: 4.2,
            y: 3
        }]
    }]
});

#container {
    min-width: 300px;
    max-width: 800px;
    height: 300px;
    margin: 1em auto;
}