Merging inner objects by ID

Question

Hi I am trying to solve a problem. Initially I am getting data from an API like so

{
   "questions":[
      {
         "id":1,
         "questionHeader":"Some question header",
         "questionText":"Some question text?",
      },
      {
         "id":2,
         "questionHeader":"Some question header",
         "questionText":"Some question text?",
      },
   ],
   "answers":[
      {
         "id":1,
         "questionId":1,
         "answer":"Some answer",
      },
      {
         "id":2,
         "questionId":1,
         "answer":"Some answer",
      },
      {
         "id":3,
         "questionId":2,
         "answer":"Some answer",
      },
   ],
    "answerText":[
      {
         "id":1,
         "answerId":1,
         "text":"Some text",
      },
      {
         "id":2,
         "answerId":2,
         "text":"Some text",
      },
      {
         "id":3,
         "answerId":3,
         "text":"Some text",
      },
   ]
}

What I was initially after was to get the answers embedded within their respective question based on a questions id and an answers questionId. So for the above, I am trying to achieve something like the following.

{
   "questions":[
      {
         "id":1,
         "questionHeader":"Some question header",
         "questionText":"Some question text?",
         "answers":[
          {
             "id":1,
             "questionId":1,
             "answer":"Some answer",
          },
          {
             "id":2,
             "questionId":1,
             "answer":"Some answer",
          },
        ]
      },
      {
         "id":2,
         "questionHeader":"Some question header",
         "questionText":"Some question text?",
         "answers":[
          {
            "id":3,
            "questionId":2,
            "answer":"Some answer",
          },
        ]
      },
   ],
}

This was achieved by doing

const newItem = data.questions.map((t1) => ({
    ...t1,
    answers: data.answers.filter((t2) => t2.questionId === t1.id),
}));

However, I now need to get the answerText embedded within the answers based on the id. So the overall format should be

{
   "questions":[
      {
         "id":1,
         "questionHeader":"Some question header",
         "questionText":"Some question text?",
         "answers":[
          {
             "id":1,
             "questionId":1,
             "answer":"Some answer",
             "answerText":[
                {
                   "id":1,
                   "answerId":1,
                   "text":"Some text",
                },
             ]
          },
          {
             "id":2,
             "questionId":1,
             "answer":"Some answer",
             "answerText":[
                {
                   "id":2,
                   "answerId":2,
                   "text":"Some text",
                },
             ]
          },
        ]
      },
      {
         "id":2,
         "questionHeader":"Some question header",
         "questionText":"Some question text?",
         "answers":[
          {
            "id":3,
            "questionId":2,
            "answer":"Some answer",
            "answerText":[
                {
                   "id":3,
                   "answerId":3,
                   "text":"Some text",
                },
             ]
          },
        ]
      },
   ],
}

How can this be achieved? Thanks

Does this answer your question? [Merge Object array based on id](https://stackoverflow.com/questions/73093474/merge-object-array-based-on-id) — pilchard, Jul 24 '22 at 09:51
You asked this question yesterday. If you were not happy with the answers, edit your original question to better describe your problem, don't post a copy of it. — pilchard, Jul 24 '22 at 09:51

score 0 · Accepted Answer · answered Jul 24 '22 at 09:43

Just by chaining the map method after filter method, and adding answerText property depending on filter the answerText array by checking the answerId is equal the answer id

const data = {
   "questions":[
      {
         "id":1,
         "questionHeader":"Some question header",
         "questionText":"Some question text?",
      },
      {
         "id":2,
         "questionHeader":"Some question header",
         "questionText":"Some question text?",
      },
   ],
   "answers":[
      {
         "id":1,
         "questionId":1,
         "answer":"Some answer",
      },
      {
         "id":2,
         "questionId":1,
         "answer":"Some answer",
      },
      {
         "id":3,
         "questionId":2,
         "answer":"Some answer",
      },
   ],
    "answerText":[
      {
         "id":1,
         "answerId":1,
         "text":"Some text",
      },
      {
         "id":2,
         "answerId":2,
         "text":"Some text",
      },
      {
         "id":3,
         "answerId":3,
         "text":"Some text",
      },
   ]
}

const newItem = data.questions.map((t1) => ({
    ...t1,
    answers: data.answers.filter((t2) => t2.questionId === t1.id).map(a1 => ({
      ...a1,
      answerText: data.answerText.filter(a2 => a2.answerId === a1.id)
    }))
}));

console.log(newItem)

Merging inner objects by ID

1 Answers1