Add a JS file - Workflow a7cff3cb

example.js

@@ -0,0 +1,88 @@
+/**
+ * example.js
+ *
+ * Representative JavaScript example file for this repo.
+ * Keeps the code dependency-free so it can run with plain Node.js.
+ *
+ * Run:
+ *   node example.js
+ */
+
+'use strict';
+
+/**
+ * Parse a CSV string into an array of objects.
+ * - Handles a header row.
+ * - Trims whitespace.
+ * - Ignores empty lines.
+ */
+function parseCSV(text) {
+  const lines = text
+    .split(/\r?\n/)
+    .map((l) => l.trim())
+    .filter(Boolean);
+
+  if (lines.length === 0) return [];
+
+  const headers = lines[0].split(',').map((h) => h.trim());
+  return lines.slice(1).map((line) => {
+    const cols = line.split(',').map((c) => c.trim());
+    return Object.fromEntries(headers.map((h, i) => [h, cols[i] ?? '']));
+  });
+}
+
+/**
+ * Group an array of items by a key function.
+ */
+function groupBy(items, keyFn) {
+  return items.reduce((acc, item) => {
+    const key = String(keyFn(item));
+    (acc[key] ??= []).push(item);
+    return acc;
+  }, /** @type {Record<string, any[]>} */ ({}));
+}
+
+/**
+ * Small demo showing parsing, transformation, grouping, and formatting.
+ */
+function main() {
+  const csv = [
+    'name, role, active',
+    'Ada,  engineer, true',
+    'Linus, engineer, true',
+    'Grace, manager, false',
+    '',
+  ].join('\n');
+
+  const users = parseCSV(csv).map((u) => ({
+    name: u.name,
+    role: u.role,
+    active: u.active.toLowerCase() === 'true',
+  }));
+
+  const activeUsers = users.filter((u) => u.active);
+  const byRole = groupBy(activeUsers, (u) => u.role);
+
+  // Pretty output
+  const summary = Object.entries(byRole)
+    .map(([role, list]) => ({ role, count: list.length, names: list.map((u) => u.name) }))
+    .sort((a, b) => b.count - a.count || a.role.localeCompare(b.role));
+
+  console.log('Active users by role:');
+  for (const row of summary) {
+    console.log(`- ${row.role}: ${row.count} (${row.names.join(', ')})`);
+  }
+
+  // Demonstrate basic error handling
+  try {
+    JSON.parse('{invalid json');
+  } catch (err) {
+    console.log('\nCaught expected error:', err instanceof Error ? err.message : String(err));
+  }
+}
+
+if (require.main === module) {
+  main();
+}
+
+module.exports = { parseCSV, groupBy };