How to merge array of objects by its key in javascript

I have a array of objects like these:

[
  {
    user: {
      key1: ['1', '2', '3'],
    },
  },
  {
    user: {
      key2: ['3', '4', '5'],
    },
  },
  {
    user2: {
      key1: ['1', '2', '3'],
    },
  },
  {
    user2: {
      key2: ['3', '4', '5'],
    },
  },
....
];

And I need to filter those by its keys and expecting an output like these

[
    {
        user: {
            key1: ['1', '2', '3'],
            key2: ['3', '4', '5'],
        },
    },
    {
        user2: {
            key1: ['1', '2', '3'],
            key2: ['3', '4', '5'],
            ....
        }
    }
]

Here user, user2 can be any key(userName) also key1, key 2 etc… may be any key(userActivity) with an array of string.

Here is the type of object:

[key: string]: {
    [key: string]: string[];
  };
}[];

Which will be the best way to filter this any help would be appreciated

>Solution :

You can do it with reduce() method:

• Iterate over each item from the data array
• Check if the key from item already exists in final result
• If it exists, concatenate current value and new value
• If it does not exist, initialize new value

const data = [
 { user: { key1: ['1', '2', '3'] } },
 { user: { key2: ['3', '4', '5'] } },
 { user2: { key1: ['1', '2', '3'] } },
 { user2: { key2: ['3', '4', '5'] } }
];

const result = data.reduce((accumulator, currentValue)=>{
  const currentKey = Object.keys(currentValue)[0];
  
  if(Object.keys(accumulator).includes(currentKey)) {
     accumulator[currentKey] = {...accumulator[currentKey], ...currentValue[currentKey]};
  } else {
     accumulator[currentKey] = currentValue[currentKey];
  }
  
  return accumulator;
},{})

console.log(result);