let say I have an array like below

let arr = [
{id:1, s:1, e: 5},
{id:2, s:6, e: 10},
{id:3, s:11, e: 15},
{id:4, s:1, e: 5},
{id:5, s:6, e: 10},
{id:6, s:11, e: 15},
{id:7, s:11, e: 15},
{id:8, s:20, e: 25},
{id:9, s:25, e: 30},
{id:10, s:20, e: 25},
]

• I have to check duplicate s and e value
• then on first occurrence object, I need to add dup key to store array of duplicate index value where duplicate element appears.
• finally i should remove all duplicate object and keep first object with duplicate keys.

expected output should be

[
{id:1, s:1, e: 5, dup: [1,4]},
{id:2, s:6, e: 10, dup: [2,5]},
{id:3, s:11, e: 15, dup: [3,6,7]},
{id:8, s:20, e: 25, dup: [8,10]},
{id:9, s:25, e: 30} // no duplicate then dup should not be added
]

I tried below but no use

const filteredArr = splits.reduce((acc, curr) => {
       let repeat = []
        const obj = acc.find((item) => {
            if (
                item.s === curr.s &&
                item.e === curr.e
            ) {
                repeat.push(item.id)
                repeat.push(curr.id)
                return true
            } else {
                return false
            }
        })
        if (obj) {
            if (!obj.isMulti) {
                obj.dup = repeat
                obj.isMulti = true
            }
            return acc
        }

        acc.push(curr)
        return acc
    }, [])
    return filteredArr

I'm not getting proper logic from where to start! any help or guidance please.

CodePudding user response：

this works but probably it isn't the most performing solution

const arr = [
{id:1, s:1, e: 5},
{id:2, s:6, e: 10},
{id:3, s:11, e: 15},
{id:4, s:1, e: 5},
{id:5, s:6, e: 10},
{id:6, s:11, e: 15},
{id:7, s:11, e: 15},
{id:8, s:20, e: 25},
{id:9, s:25, e: 30},
{id:10, s:20, e: 25},
]

const groupDuplicates = (data) => {

const set = [...new Set(data.map(({s, e}) => JSON.stringify({s,e})))]

return set.map(el => {
 const {s, e} = JSON.parse(el)
 const matching = data.filter(d => d.s === s && d.e === e)
 if(matching.length === 1){
   return {id: matching[0].id, s, e}
 }
 return {
   id: matching[0].id,
   s,
   e,
   dup: matching.map(m => m.id)
 } 
})
}

console.log(groupDuplicates(arr))

CodePudding user response：

You could group with an object and add dup, if necessary and add the actual id to it.

const
    array = [{ id: 1, s: 1, e: 5 }, { id: 2, s: 6, e: 10 }, { id: 3, s: 11, e: 15 }, { id: 4, s: 1, e: 5 }, { id: 5, s: 6, e: 10 }, { id: 6, s: 11, e: 15 }, { id: 7, s: 11, e: 15 }, { id: 8, s: 20, e: 25 }, { id: 9, s: 25, e: 30 }, { id: 10, s: 20, e: 25 }],
    keys = ['s', 'e'],
    getKey = o => keys.map(k => o[k]).join('|'),
    result = Object.values(array.reduce((r, o) => {
        const key = getKey(o);
        if (r[key]) (r[key].dup ??= [r[key].id]).push(o.id);
        else r[key] = { ...o };
        return r;
    }, {}));

console.log(result);

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CodePudding user response：

You can use an object to keep track of repeated ${s}_${e} combinations and get an array from it

let arr = [
  {id:1, s:1, e: 5},
  {id:2, s:6, e: 10},
  {id:3, s:11, e: 15},
  {id:4, s:1, e: 5},
  {id:5, s:6, e: 10},
  {id:6, s:11, e: 15},
  {id:7, s:11, e: 15},
  {id:8, s:20, e: 25},
  {id:9, s:25, e: 30},
  {id:10, s:20, e: 25},
]

const dups = Object.values(arr.reduce((hash, curr) => {
  const {id, s, e} = curr;
  const key = `${s}_${e}`;
  if(key in hash) {
    return (hash[key].dup ??= [hash[key].id]).push(id), hash;
  }
  return hash[key] = {...curr}, hash;
}, {}))
console.log(dups)