refactoring

docs/HistogramChartView.js

@@ -0,0 +1,62 @@
+class HistogramChartView {
+
+    #canvas;
+    #chart;
+
+    constructor(canvas) {
+        this.#canvas = canvas;
+    }
+
+    displayChart(histoDescr) {
+        if (this.#chart != null) {
+            this.#chart.destroy();
+        }
+        this.#chart = new Chart(
+            this.#canvas,
+            {
+                type: 'bar',
+                data: this.#getData(histoDescr),
+                options: this.#getOptions()
+            });
+    }
+
+    // setData(data) {
+    //     this.#chart.config.data.datasets[0].data = data;
+    //     this.#chart.update();
+    // }
+
+    #getData(histoDescr) {
+        const { 'keys': symptoms, 'values': frequencies } = Utils.getKeysAlignedWithValues(histoDescr.histogram);
+        return {
+            labels: symptoms,
+            datasets: [{
+                label: histoDescr.batchcodes.join(', '),
+                data: frequencies
+            }]
+        };
+    }
+
+    #getOptions() {
+        return {
+            indexAxis: 'y',
+            responsive: true,
+            scales: {
+                y: {
+                    title: {
+                        display: true,
+                        text: 'Symptom'
+                    }
+                },
+                x: {
+                    ticks: {
+                        precision: 0
+                    },
+                    title: {
+                        display: true,
+                        text: 'Frequency'
+                    }
+                }
+            }
+        };
+    }
+}