[Solved] Recursively Search Through a Flat Array

you can do like this fiddle,

function getChildren(id){
  let result = [];
  $.each(orig, function(i, d) {
     if (d.parent === id) {
            result.push(d);
        result.push(...getChildren(d.id));
     }
  });
  return result;
}

console.log(getChildren('Test'));