Lodash and merge of Arrays with Key

Question

I am able to merge objects stored in array fine with lodash but what I need is the find a way to merge based on a key which is part of the object. If I don't use key, the merge is not reliable as when a doc is returned out of order, as it will create an invalid merge. So I hope that there is a way to merge based on a key value, in my case its id.

Here is some sample:

Doc 1

[
    {
         "id": 123,
         "Key1": "Test 1",
         "Key3": "Test 0"
    },
    {
         "id": 456,
         "Key1": "Test 2",
         "Key2": "Test 3"
    }
]

Doc 2

[

    {
         "id": 123,
         "Key2": "Test 7",
         "Key3": "Test 8"
    },
    {
         "id": 789,
         "Key1": "Test 5",
         "Key2": "Test 6"
    }
]

Based on the simple sample above i am looking for an output like this

[
    {
         "id": 123,
         "Key1": "Test 1",
         "Key2": "Test 7",
         "Key3": "Test 8"
    },
    {
         "id": 456,
         "Key1": "Test 2",
         "Key2": "Test 3"
    },
    {
         "id": 789,
         "Key1": "Test 5",
         "Key2": "Test 6"
    }
]

Answer 1

const addKeys = (results, keys) => keys.reduce(
  (final, item) => {
    const id = item.id;
    let current = final.find(i => i.id === id);
    if (!current) {
      current = { id: id };
      final.push(current);
    }
    Object.keys(item).forEach(key => { current[key] = item[key] });
    return final;
  }, results
);

console.log(addKeys(
  [
      {
           "id": 123,
           "Key1": "Test 1",
           "Key3": "Test 0"
      },
      {
           "id": 456,
           "Key1": "Test 2",
           "Key2": "Test 3"
      }
  ],
  [

      {
           "id": 123,
           "Key2": "Test 7",
           "Key3": "Test 8"
      },
      {
           "id": 789,
           "Key1": "Test 5",
           "Key2": "Test 6"
      }
  ]
));