feat: insert csv columns

src/pages/tools/csv/insert-csv-columns/service.ts

@@ -0,0 +1,81 @@
+import { InitialValuesType } from './types';
+import { splitCsv } from '@utils/csv';
+import { transpose, normalizeAndFill } from '@utils/array';
+
+export function main(input: string, options: InitialValuesType): string {
+  if (!input || !options.csvToInsert) return '';
+
+  // Parse input CSV and insert CSV
+  const inputRows = splitCsv(
+    input,
+    true,
+    options.commentCharacter,
+    true,
+    options.separator,
+    options.quoteChar
+  );
+
+  const filledRows = options.customFill
+    ? normalizeAndFill(inputRows, options.customFillValue)
+    : normalizeAndFill(inputRows, '');
+
+  let columns = transpose(filledRows);
+
+  const csvToInsertRows = splitCsv(
+    options.csvToInsert,
+    true,
+    options.commentCharacter,
+    true,
+    options.separator,
+    options.quoteChar
+  );
+
+  const filledCsvToInsertRows = options.customFill
+    ? normalizeAndFill(csvToInsertRows, options.customFillValue)
+    : normalizeAndFill(csvToInsertRows, '');
+
+  const columnsToInsert = transpose(filledCsvToInsertRows);
+
+  switch (options.insertingPosition) {
+    case 'prepend':
+      columns = [...columnsToInsert, ...columns];
+      break;
+
+    case 'append':
+      columns = [...columns, ...columnsToInsert];
+      break;
+
+    case 'custom':
+      if (options.customPostionOptions === 'headerName') {
+        const headerName = options.headerName;
+        const index = filledRows[0].indexOf(headerName);
+        if (index !== -1) {
+          columns = [
+            ...columns.slice(0, index + 1),
+            ...columnsToInsert,
+            ...columns.slice(index + 1)
+          ];
+        } // else: keep original columns
+      } else if (options.customPostionOptions === 'rowNumber') {
+        const index = options.rowNumber;
+        if (index >= 0 && index <= columns.length) {
+          columns = [
+            ...columns.slice(0, index),
+            ...columnsToInsert,
+            ...columns.slice(index)
+          ];
+        } // else: keep original columns
+      }
+      break;
+
+    default:
+      // no-op, keep original columns
+      break;
+  }
+
+  // Transpose back to rows
+  const normalizedColumns = normalizeAndFill(columns, options.customFillValue);
+  const finalRows = transpose(normalizedColumns);
+
+  return finalRows.map((row) => row.join(options.separator)).join('\n');
+}