[рони]

darktowerk56c,
или так

<script>
const obj = {
    one: ['1', '2', '3'],
    two: ['4', '5', '6'],
    three: ['7', '8', '9'],
    four: ['10', '11', '12'],
}
const arr = Object.entries(obj).map(([key, value]) => ({[key] : value}));
document.write(JSON.stringify(arr, "", 4))
  </script>