Bug in solution of this task: https://javascript.info/array-methods#create-keyed-object-from-array

There's a bug in the solution posted in this task.
The task requires us to group objects by id and put the grouped objects in an array keyed by id.
The solution posted is:

function groupById(array) {
  return array.reduce((obj, value) => {
    obj[value.id] = value;
    return obj;
  }, {})
}

However, this does not work when there are items in array with same id.
To accomplish the task correctly, the solution should be:

function groupById(array) {
  return array.reduce((obj, value) => {
    obj[value.id] == undefined ? obj[value.id] = [value] : obj[value.id].push(value);
    return obj;
  }, {})
}

Open the array-methods task at javascript.info/array-methods#create-keyed-object-from-array and compare the stated grouping requirement with the posted reduce solution. Update the documented solution so repeated IDs retain all grouped objects, then verify the example and explanation still match the corrected result.