Group objects based on similar value in array of objects

Question

I have an array of objects I want to group/merge the objects which have similar branches and environments and concat their pools at the same time.

const data = [
  {
    branch: "master",
    environment: "dev",
    pool: "6g",
    service: "amex",
  },
  {
    branch: "master",
    environment: "dev",
    pool: "6g",
    service: "amex",
  },
  {
    branch: "feature/rest",
    environment: "dev",
    pool: "2g",
    service: "amex",
  },
  {
    branch: "master",
    environment: "dev",
    pool: "4g",
    service: "amex",
  },
  {
    branch: "hotfix/23",
    environment: "test",
    pool: "9g",
    service: "amex",
  },
  {
    branch: "hotfix/23",
    environment: "test",
    pool: "1g",
    service: "amex",
  },
];

I want the result in the below format removing duplicate objects as well I tried to reduce it but as array reduce returns a single object as a result and the other objects are being omitted from the response what data structure or way I can use to achieve the result?

const result = [
  {
    branch: "master",
    environment: "dev",
    pool: "6g, 4g",
    service: "amex",
  },
  {
    branch: "feature/rest",
    environment: "dev",
    pool: "2g",
    service: "amex",
  },
  {
    branch: "hotfix/23",
    environment: "test",
    pool: "9g,1g",
    service: "amex",
  },
];

How i can compare two objects in map, in reduce i had accumulator and i can compare? — giiyiraj
– giiyiraj, Commented Jun 3, 2022 at 15:20
I recommend filtering your array based on each branch for exmaple master , and then work with new created arrays — Moein Moeinnia
– Moein Moeinnia, Commented Jun 3, 2022 at 15:24
Does this answer your question? How to group an array of objects based on multiple keys in Javascript? — pilchard
– pilchard, Commented Jun 3, 2022 at 15:44

Albi · Accepted Answer · 2022-06-03 16:10:53Z

5

const data = [{
    branch: "master",
    environment: "dev",
    pool: "6g",
    service: "amex",
  },
  {
    branch: "feature/rest",
    environment: "dev",
    pool: "2g",
    service: "amex",
  },
  {
    branch: "master",
    environment: "dev",
    pool: "4g",
    service: "amex",
  },
  {
    branch: "hotfix/23",
    environment: "test",
    pool: "9g",
    service: "amex",
  },
  {
    branch: "hotfix/23",
    environment: "test",
    pool: "1g",
    service: "amex",
  },
];

var cacheMix = {};

for (var i = 0; i < data.length; i++) {

  var item = data[i];
  var compositeKey = item.environment + "~" + item.branch;

  if (cacheMix[compositeKey]) {
    cacheMix[compositeKey].pools[item.pool] = 1;
  } else {
    var pools = {}; pools[item.pool] = 1; //to avoid dublicate pools 
    cacheMix[compositeKey] = {
      branch: item.branch,
      environment: item.environment,
      service: item.service,
      pools: pools 
    }
  }
}


var result = [];


for (var key in cacheMix) {

  var item = cacheMix[key];
  result.push({
    branch: item.branch,
    environment: item.environment,
    service: item.service,
    pool: Object.keys(item.pools).join(", ")
  });
}

console.log(result);

edited Jun 3, 2022 at 16:10

answered Jun 3, 2022 at 15:23

Albi

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5 Comments

Albi Over a year ago

This approach loops just the minimal number of times through the items. For better performance never use array reduce

pbialy Over a year ago

Reducing the time which developers will spend while trying to understand your code is, in most cases, much more important than some micro-optimalisation ;)

Albi Over a year ago

I don't know maybe I am the old school weirdo that reads it better this way

giiyiraj Over a year ago

Thanks for the solution I think I just noticed is the input array also contains duplicates(same object twice) so the result object has the same pools concated for eg pool: 5g, 5g, 6g

Albi Over a year ago

That is very easy to fix just use object for pools and join the Object.keys(item.pools) at the end and no dublicates. Edited the code so it will not happen. I would appreciate if you mark the answer as correct so other developers of the community will not spend more time on this

AMunim · Accepted Answer · 2022-06-03 17:01:16Z

Just create a dictionary out of them and fill in the values.

const data=[{branch:"master",environment:"dev",pool:"6g",service:"amex"},{branch:"feature/rest",environment:"dev",pool:"2g",service:"amex"},{branch:"master",environment:"dev",pool:"4g",service:"amex"},{branch:"hotfix/23",environment:"test",pool:"9g",service:"amex"},{branch:"hotfix/23",environment:"test",pool:"1g",service:"amex"},]


let x = {};
data.forEach(y => x[y.branch + "|" + y.environment] = y);

var res = Object.values(x).map(y => Object.assign({}, y)).map(y => 
{
    y.pool = data.filter(d => d.branch == y.branch && d.environment == y.environment).map(x => x.pool).join(",");
   return y;
})

If you do not care about immutability(original objects in data change), then remove Object.assign map and it will yield the same results

Terry Lennox · Accepted Answer · 2022-06-03 15:42:01Z

I'd suggest using Array.reduce() for this, creating a map of the data using a key created from the branch and environment.

Once we have the map object, we can use Object.values() to return an array of the desired results.

const data = [ { branch: "master", environment: "dev", pool: "6g", service: "amex", }, { branch: "feature/rest", environment: "dev", pool: "2g", service: "amex", }, { branch: "master", environment: "dev", pool: "4g", service: "amex", }, { branch: "hotfix/23", environment: "test", pool: "9g", service: "amex", }, { branch: "hotfix/23", environment: "test", pool: "1g", service: "amex", }, ];

const result = Object.values(data.reduce((acc, { branch, environment, pool, service }) => {
    // Our grouping key...
    const key = `${branch}-${environment}`;
    acc[key] = acc[key] || { branch, environment, pool: '', service };
    acc[key].pool += ((acc[key].pool ? ", " : "" ) + pool);
    return acc;
}, {}))

console.log('Result:', result)

.as-console-wrapper { max-height: 100% !important; }

symlink · Accepted Answer · 2022-06-03 15:51:33Z

This is one way to do it:

const data=[{branch:"master",environment:"dev",pool:"6g",service:"amex"},{branch:"feature/rest",environment:"dev",pool:"2g",service:"amex"},{branch:"master",environment:"dev",pool:"4g",service:"amex"},{branch:"hotfix/23",environment:"test",pool:"9g",service:"amex"},{branch:"hotfix/23",environment:"test",pool:"1g",service:"amex"},]

const res = data.reduce((acc, cur) =>
{
    let isMatch = false
    acc.forEach((el, idx) => {
        if(el.branch === cur.branch && el.environment === cur.environment) {
            if(acc[idx].service !== cur.service) {
                acc[idx].service += `, ${cur.service}`
            }
            if(acc[idx].pool !== cur.pool) {
                acc[idx].pool += `, ${cur.pool}`
            }
            isMatch = true
        }
    })
    if(!isMatch) {
        acc.push(cur)    
    }
    
    return acc
}, [])

console.log(res)

pbialy · Accepted Answer · 2022-06-03 15:58:44Z

0

data.reduce((prev, curr) => {
  const container = prev.find(
    el => (el.branch === curr.branch) && (el.environment === curr.environment)
  );
  if (container) {
    container.pool = container.pool + `,${curr.pool}`
    return prev;
  } else {
    return prev.concat({...curr}) 
  }
}, [])

but I would suggest to instead create an object with keys equal to branch names.

edited Jun 3, 2022 at 15:58

answered Jun 3, 2022 at 15:35

pbialy

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