arr1 = [{3265: {…}}, {3266: {…}}]
arr2 = [{3265: {…}}, {3267: {…}}]
result = [{3265: {…}}, {3266: {…}}, {3267: {…}}] 
  
  const result = Object
  .entries(Object.assign({}, ...arr1, ...arr2))
  .map(n => ({ [n[0]]: n[1] }));const union = (key, ...arrs) =>
  Object.values([]
    .concat(...arrs)
    .reduce((acc, n) => (acc[key(n)] = n, acc), {})
  );
const result = union(el => Object.keys(el)[0], arr1, arr2);const result = _.unionBy(arr1, arr2, el => _.keys(el)[0]);