Group Array Of Objects By Value And Get Count Of The Groups

I have an array objects [ { group: 1 }, { group: 2 ], { group: 2 } ] I want to get the count of distinct groups by property value 'group', expecting the result of 2 How to do this

Solution 1:

You just need to store counts in your aggregator for each key using reduce.

const data = [ { 'group': 1 }, { 'group': 2 }, { 'group': 2 } ]

const groups = data.reduce((agg, curr)=>{
  if(agg[curr.group]){
    agg[curr.group] += 1
    }
  else{
    agg[curr.group] = 1
  }
  return agg
},{})

console.log(groups)

Solution 2:

i'm not sure that i understand your question right. If you want group your object by value equals to 2, using filter will be useful

const obj = [ { group: 1 }, { group: 2 }, { group: 2 }, { group: 2 } ]

// new array with group value equals to 2const countGroup = () => {
      return obj.filter(it => it.group === 2)
    }

// count how many group with value equals to 2const countGroupCount = () => {
      return obj.filter(it => it.group === 2)
    }

    console.log(countGroup())
console.log(countGroupCount())