How to merge array of objects by its key in javascript

Question

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

Answer 1

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);

Answer 2

an idea with array.reduce

 var data = [{ user: { key1: ['1', '2', '3'], }, }, { user: { key2: ['3', '4', '5'], }, }, { user2: { key1: ['1', '2', '3'], }, }, { user2: { key2: ['3', '4', '5'], }, } ]; let result = data.reduce((acc, curr) => { Object.keys(curr).forEach(key => { let found = acc.find(elem => elem[key]); if (found) { found[key] = {...found[key], ...curr[key]} } else { acc.push(curr); } }); return acc; }, []); console.log(result);

Answer 3

Something like this perhaps

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

let result = initial.reduce((acc, curr)=>{
    if(Object.keys(curr)[0]) {
        const key =Object.keys(curr)[0]
        const values = curr[key]
        acc = {
            ...acc,
            [key]: {
                ...acc[key],
                ...values
            }
        }
        return acc
    }
},[])