Refactored components used to render charts for visits

src/visits/charts/HorizontalBarChart.tsx

@@ -0,0 +1,131 @@
+import { FC } from 'react';
+import { ChartData, ChartDataset, ChartOptions } from 'chart.js';
+import { keys, values } from 'ramda';
+import { Bar } from 'react-chartjs-2';
+import { fillTheGaps } from '../../utils/helpers/visits';
+import { pointerOnHover, renderChartLabel } from '../../utils/helpers/charts';
+import { prettify } from '../../utils/helpers/numbers';
+import { Stats } from '../types';
+import { HIGHLIGHTED_COLOR, HIGHLIGHTED_COLOR_ALPHA, MAIN_COLOR, MAIN_COLOR_ALPHA } from '../../utils/theme';
+
+export interface HorizontalBarChartProps {
+  stats: Stats;
+  max?: number;
+  highlightedStats?: Stats;
+  highlightedLabel?: string;
+  onClick?: (label: string) => void;
+}
+
+const dropLabelIfHidden = (label: string) => label.startsWith('hidden') ? '' : label;
+const statsAreDefined = (stats: Stats | undefined): stats is Stats => !!stats && Object.keys(stats).length > 0;
+const determineHeight = (labels: string[]): number | undefined => labels.length > 20 ? labels.length * 10 : undefined;
+
+const generateChartDatasets = (
+  data: number[],
+  highlightedData: number[],
+  highlightedLabel?: string,
+): ChartDataset[] => {
+  const mainDataset: ChartDataset = {
+    data,
+    label: highlightedLabel ? 'Non-selected' : 'Visits',
+    backgroundColor: MAIN_COLOR_ALPHA,
+    borderColor: MAIN_COLOR,
+    borderWidth: 2,
+  };
+
+  if (highlightedData.every((value) => value === 0)) {
+    return [ mainDataset ];
+  }
+
+  const highlightedDataset: ChartDataset = {
+    label: highlightedLabel ?? 'Selected',
+    data: highlightedData,
+    backgroundColor: HIGHLIGHTED_COLOR_ALPHA,
+    borderColor: HIGHLIGHTED_COLOR,
+    borderWidth: 2,
+  };
+
+  return [ mainDataset, highlightedDataset ];
+};
+const generateChartData = (
+  labels: string[],
+  data: number[],
+  highlightedData: number[],
+  highlightedLabel?: string,
+): ChartData => ({
+  labels,
+  datasets: generateChartDatasets(data, highlightedData, highlightedLabel),
+});
+
+type ClickedCharts = [{ index: number }] | [];
+const chartElementAtEvent = (labels: string[], onClick?: (label: string) => void) => ([ chart ]: ClickedCharts) => {
+  if (!onClick || !chart) {
+    return;
+  }
+
+  onClick(labels[chart.index]);
+};
+
+export const HorizontalBarChart: FC<HorizontalBarChartProps> = (
+  { stats, highlightedStats, highlightedLabel, onClick, max },
+) => {
+  const labels = keys(stats).map(dropLabelIfHidden);
+  const data = values(
+    !statsAreDefined(highlightedStats) ? stats : keys(highlightedStats).reduce((acc, highlightedKey) => {
+      if (acc[highlightedKey]) {
+        acc[highlightedKey] -= highlightedStats[highlightedKey];
+      }
+
+      return acc;
+    }, { ...stats }),
+  );
+  const highlightedData = fillTheGaps(highlightedStats ?? {}, labels);
+
+  const options: ChartOptions = {
+    plugins: {
+      legend: { display: false },
+      tooltip: {
+        mode: 'y',
+        // Do not show tooltip on items with empty label when in a bar chart
+        filter: ({ label }) => label !== '',
+        callbacks: { label: renderChartLabel },
+      },
+    },
+    scales: {
+      x: {
+        beginAtZero: true,
+        stacked: true,
+        max,
+        ticks: {
+          precision: 0,
+          callback: prettify,
+        },
+      },
+      y: { stacked: true },
+    },
+    onHover: pointerOnHover,
+    indexAxis: 'y',
+  };
+  const chartData = generateChartData(labels, data, highlightedData, highlightedLabel);
+  const height = determineHeight(labels);
+
+  // Provide a key based on the height, to force re-render every time the dataset changes (example, due to pagination)
+  const renderChartComponent = (customKey: string) => (
+    <Bar
+      key={`${height}_${customKey}`}
+      data={chartData}
+      options={options}
+      height={height}
+      getElementAtEvent={chartElementAtEvent(labels, onClick) as any}
+    />
+  );
+
+  return (
+    <>
+      {/* It's VERY IMPORTANT to render two different components here, as one has 1 dataset and the other has 2 */}
+      {/* Using the same component causes a crash when switching from 1 to 2 datasets, and then back to 1 dataset */}
+      {highlightedStats !== undefined && renderChartComponent('with_stats')}
+      {highlightedStats === undefined && renderChartComponent('without_stats')}
+    </>
+  );
+};