const { ChartJSNodeCanvas } = require('chartjs-node-canvas');
const fs = require("fs");
const width = 1080; //px
const height = 540; //px
const for_chart_labels = ['01.02.2021 Пн/Mon', '02.02.2021 Вт/Tue', '03.02.2021 Ср/Wed', '04.02.2021 Чт/Thu', '05.02.2021 Пт/Fri', '06.02.2021 Сб/Sat', '07.02.2021 Вс/Sun'];
const for_chart_data = [8706, 2725, 6821, 7602, 8452, 0, 8205];
const chartJSNodeCanvas = new ChartJSNodeCanvas({ width, height });

(async () => {
    const configuration = {
        type: "bar",
        data: {
            labels: for_chart_labels,
            datasets: [{
                label: "",
                borderWidth: 2,
                borderColor: [
                    "rgb(255, 99, 132)",
                    "rgb(54, 162, 235)",
                    "rgb(255, 206, 86)",
                    "rgb(75, 192, 192)",
                    "rgb(153, 102, 255)",
                    "rgb(255, 159, 64)",
                    "rgb(255, 99, 132)"
                ],
                data: for_chart_data,
                backgroundColor: [
                "rgba(255, 99, 132, 0.2)",
                "rgba(54, 162, 235, 0.2)",
                "rgba(255, 206, 86, 0.2)",
                "rgba(75, 192, 192, 0.2)",
                "rgba(153, 102, 255, 0.2)",
                "rgba(255, 159, 64, 0.2)",
                "rgba(255, 99, 132, 0.2)"
            ]
            }]
        },
        options: {
            legend: {
                display: false
            },
            scales: {
                xAxes: [{
                    gridLines: {
                        display: false,
                    },
                    ticks: {
                        display: false
                    }
                }],
                yAxes: [{
                    gridLines: {
                        display: false,
                    },
                    ticks: {
                        display: false
                    }
                }]
            }
    }};
    const image = await chartJSNodeCanvas.renderToBuffer(configuration);

    fs.writeFile("./hello.png", image, function(error){
        if(error) throw error; // если возникла ошибка

    });
})();