EasyJavaScriptPractice mode: untimed, 3 hints

First overdue invoice

firstOverdue(invoices, today) returns the id of the first invoice that is unpaid and due before today, or null if there is none. Dates are "YYYY-MM-DD" strings, which compare correctly as text.

The code has exactly one planted bug. Reproduce it with the tests, fix it with the smallest change, then submit.

Visible tests

paid invoice first
- firstOverdue([{"id":"A","due":"2026-01-10","paid":true},{"id":"B","due":"2026-01-05","paid":false}], "2026-02-01") → "B"
not due yet
- firstOverdue([{"id":"C","due":"2026-03-01","paid":false}], "2026-02-01") → null

Hints 0/3

// Returns the id of the first unpaid invoice that is past its due date, or null.
// Dates are "YYYY-MM-DD" strings, so they compare correctly as text.
function firstOverdue(invoices, today) {
  for (const inv of invoices) {
    if (!inv.paid && inv.due < today) {
      return inv.id;
    } else {
      return null;
    }
  }
  return null;
}

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