[Chartjs]-Chartjs show 24 hours in line chart

Since you did not provide how you initialize the chartjs plugin, assume you have this configuration of line chart, the labels are date that shown on the x-axis, label is the chart name shown on top, and the data is the sum of the count that will be calculated.

var dataset = [{
    "hour": "2018-03-18T00:00:00.000Z",
    "count": 230
    }, {
    "hour": "2018-03-18T04:00:00.000Z",
    "count": 450
}];

// group the dataset by date

var dataGroup = [];  // array of { date : count } 
for (var idx in dataset) {
    var date = dataset[idx]['hour'].substr(0, 10);
    dataGroup[date] = dataGroup[date] || 0;
    dataGroup[date] += dataset[idx]['count'];
}

var labels = []; // labels shown on the x-axis
var data = []; // sum of count group by date
for (var date in dataGroup) {
    labels.push(date);
    data.push(dataGroup[date]);
}

var ctx = document.getElementById("chart").getContext("2d");
new Chart(ctx, {
    type: 'line',
    data: {
        labels: labels,
        datasets: [
            label: label,
            data: data,
            fillColor: "#79D1CF",
            strokeColor: "#79D1CF",
        ]
    }
});