_Layout.cshtml:

    <script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.6.0/Chart.js"></script>
    <script>
     function createChart(options) {  
         var element = document.getElementById(options.canvasId);
         var ctx = element.getContext("2d");
         var myLine = new Chart(ctx, {
             type:options.chartType,
             data:options.chartData,
             showTooltips: false,
             onAnimationComplete: window[options.onAnimationComplete]
          });
     }     
    </script>

Index.Razor page:

    @page "/"
    @inject IJSRuntime JS
    <PageTitle>Index</PageTitle>
    <p>
        <button @onclick="SetStock">Set Stock</button>
    </p>

    <canvas id="myChart1" height="300" width="500"></canvas>
    <canvas id="myChart2" height="300" width="500"></canvas>
    @code {
        private async Task SetStock()
        {
            await JS.InvokeVoidAsync("createChart", new
            {
                canvasId = "myChart1",
                onAnimationComplete = "function1",
                chartType= "line",
                chartData = new
                {
                    labels = new string[] { "January", "February", "March", "April", "May", "June" },
                    datasets = new object[]
                        {
                            new
                            {
                                fillColor = "#79D1CF",
                                strokeColor = "#79D1CF",
                                data = new int[] { 60, 80, 81, 56, 55, 40 }
                            }
                        }
                }
            });
        }
    }