JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.2.1/Chart.min.js"></script>
<div class="myChartDiv">
    <canvas id="myChart" width="600" height="400"></canvas>
</div>

CSS

.myChartDiv {
    max-width: 600px;
    max-height: 400px;
}

JavaScript

var ctx = document.getElementById("myChart");
var borderColors = ['red','blue','black']
var myChart = new Chart(ctx, {
    type: 'bar',
    data: {
        labels: ["Red", "Blue", "Black"],
        datasets: [{
            label: '# of Votes',
            data: [12, 19, 3],
            borderColor:borderColors,
            borderWidth:3,
            borderStyle:'dash'//has no effect
        }]
    }
});

function dashedBorder(chart, dataset, data, dash) {
	chart.config.data.datasets[dataset]._meta[0].data[data].draw = function() {
        chart.chart.ctx.setLineDash(dash);
        Chart.elements.Rectangle.prototype.draw.apply(this, arguments);
        chart.chart.ctx.setLineDash([1,0]);
    }
}

// dashedBprder(chart, datasetIndex, barIndex, dash values)
dashedBorder(myChart, 0, 0, [15,10]);
dashedBorder(myChart, 0, 2, [5,15]);

console.log(myChart);