CODEWITHSUNDEEP
javascriptarraysjsonobject
Mark
Mark

Reputation: 27

Group items by common property in array of objects

I'm looking for an efficient way to rearrange an array of objects in JS. I need to combine two parameters from each object into a single object, where the gwdetailsid value is the same.

Initial array:

{
  "data": [
    {
      "gwdetailsid": "gw1",
      "gwpname": "username",
      "gwpvalue": "transalis"
    },
    {
      "gwdetailsid": "gw1",
      "gwpname": "password",
      "gwpvalue": "secure_password@1"
    },
    {
      "gwdetailsid": "gw2",
      "gwpname": "username",
      "gwpvalue": "tesco"
    },
    {
      "gwdetailsid": "gw2",
      "gwpname": "password",
      "gwpvalue": "lemon_farmer_2"
    }
  ]
}

The desired output array:

{
  "gateways": [
    {
      "gwdetailsid": "gw1",
      "username": "transalis",
      "password": "secure_password@1"
    },
    {
      "gwdetailsid": "gw2",
      "username": "tesco",
      "password": "lemon_farmer_2"
    }
  ]
}

Upvotes: 0

Views: 299

Answers (1)

Yevhen Horbunkov
Yevhen Horbunkov

Reputation: 15530

Effectively, your task comes down to transforming data array into gateways array.

You may employ Array.prototype.reduce() for that kind of job, to build up the Map with gwdetailsid property as a key, then extract .values() of that Map:

const data = [{gwdetailsid:"gw1",gwpname:"username",gwpvalue:"transalis"},{gwdetailsid:"gw1",gwpname:"password",gwpvalue:"secure_password@1"},{gwdetailsid:"gw2",gwpname:"username",gwpvalue:"tesco"},{gwdetailsid:"gw2",gwpname:"password",gwpvalue:"lemon_farmer_2"}],
      
      gateways = [...data
        .reduce((acc, {gwdetailsid, gwpname, gwpvalue} ) => {
          const group = acc.get(gwdetailsid)
          group
            ? group[gwpname] = gwpvalue
            : acc.set(gwdetailsid, {gwdetailsid, [gwpname]: gwpvalue})
          return acc
        }, new Map)
        .values()
      ]
      
console.log(gateways)
.as-console-wrapper{min-height:100%;}

Upvotes: 1

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