reconstruct

services/pivot_table.ts

@@ -0,0 +1,36 @@
+import { analytics } from './analytics_engine'; // Import your analytics engine
+
+export interface PivotOptions {
+  index: string[];
+  columns: string[];
+  values: string;
+  aggFunc?: (items: number[]) => number; // Aggregation function (e.g., analytics.mean)
+}
+
+export function pivotTable(
+  data: Record<string, any>[],
+  options: PivotOptions
+): Record<string, Record<string, number>> {
+  const { index, columns, values, aggFunc = arr => arr.reduce((a, b) => a + b, 0) } = options;
+  const cellMap: Record<string, Record<string, number[]>> = {};
+
+  data.forEach(row => {
+    const rowKey = index.map(k => row[k]).join('|');
+    const colKey = columns.map(k => row[k]).join('|');
+
+    if (!cellMap[rowKey]) cellMap[rowKey] = {};
+    if (!cellMap[rowKey][colKey]) cellMap[rowKey][colKey] = [];
+    cellMap[rowKey][colKey].push(row[values]);
+  });
+
+  // Apply aggregation function to each cell
+  const result: Record<string, Record<string, number>> = {};
+  Object.entries(cellMap).forEach(([rowKey, cols]) => {
+    result[rowKey] = {};
+    Object.entries(cols).forEach(([colKey, valuesArr]) => {
+      result[rowKey][colKey] = aggFunc(valuesArr);
+    });
+  });
+
+  return result;
+}