Merging multiple JSON objects from an array together

Question

I have an array of JSON objects and I want to merge the objects that have the same text together while finding the average of relevance and the sum of count across all of the same instances.

var keywords = [
            {
                "text": "service businesses",
                "relevance": 0.626303,
                "count": 1
            },
            {
                "text": "service businesses",
                "relevance": 0.87319,
                "count": 5
            },
            {
                "text": "service businesses",
                "relevance": 0.05,
                "count": 100
            },
            {
                "text": "restaurants",
                "relevance": 0.614567,
                "count": 16
            },
            {
                "text": "restaurants",
                "relevance": 0.609875,
                "count": 4
            },
            {
                "text": "hotels",
                "relevance": 0.594905,
                "count": 1
            },

I tried the solution posted here but, I am getting an output like this:

{
    text: 'service businesses',
    count: '[object Object][object Object]'
  }

The output I am hoping for would look like this:

            {
                "text": "service businesses",
                "relevance": 0.516497667,
                "count": 106
            },

            {
                "text": "restaurants",
                "relevance": 0.612221,
                "count": 20
            },
            {
                "text": "hotels",
                "relevance": 0.594905,
                "count": 1
            },

Any help is much appreciated!

Answer 1

Using Array.prototype.reduce, you can group the elements by the text and based on that group data, can get the output as follows.

var keywords = [{
    "text": "service businesses",
    "relevance": 0.626303,
    "count": 1
  },
  {
    "text": "service businesses",
    "relevance": 0.87319,
    "count": 5
  },
  {
    "text": "service businesses",
    "relevance": 0.05,
    "count": 100
  },
  {
    "text": "restaurants",
    "relevance": 0.614567,
    "count": 16
  },
  {
    "text": "restaurants",
    "relevance": 0.609875,
    "count": 4
  },
  {
    "text": "hotels",
    "relevance": 0.594905,
    "count": 1
  }
];

const groupBy = keywords.reduce((acc, cur) => {
  acc[cur.text] ? acc[cur.text] = {
    ...acc[cur.text],
    count: acc[cur.text].count + cur.count,
    relevance: [...acc[cur.text].relevance, cur.relevance]
  } : acc[cur.text] = {
    ...cur,
    relevance: [cur.relevance]
  };
  return acc;
}, {});
const output = Object.values(groupBy).map((item) => ({
  ...item,
  relevance: item.relevance.reduce((acc, cur) => acc + cur, 0) / item.relevance.length
}));
console.log(output);