Order Array of objects by parentId-CodePudding

I am trying to group an array of objects from a parentId that each element of the array brings, there can always be an indeterminate number of levels, the result I expect is the one I have in the output.

I have done the first level and it creates the first subgroup of chlds well, but I don't know how generate the following ones.

INPUT

const data = [
{
    "groupid": 1,
    "parentid": 0,
    "usrdesc": "Principal"
},
{
    "groupid": 43,
    "parentid": 1,
    "usrdesc": "Opers"
},
{
    "groupid": 44,
    "parentid": 43,
    "usrdesc": "London"
},
{
    "groupid": 45,
    "parentid": 44,
    "usrdesc": "Sells"
},
{
    "groupid": 46,
    "parentid": 45,
    "usrdesc": "grp"
},
{
    "groupid": 89,
    "parentid": 46,
    "usrdesc": "PFG"
},
{
    "groupid": 48,
    "parentid": 44,
    "usrdesc": "WEF"
},
{
    "groupid": 49,
    "parentid": 44,
    "usrdesc": "API"
},
{
    "groupid": 50,
    "parentid": 49,
    "usrdesc": "CTX"
},
{
    "groupid": 142,
    "parentid": 44,
    "usrdesc": "CSS"
},
{
    "groupid": 58,
    "parentid": 1,
    "usrdesc": "ASD"
},
{
    "groupid": 71,
    "parentid": 58,
    "usrdesc": "CZX"
},
{
    "groupid": 106,
    "parentid": 58,
    "usrdesc": "RTE"
},
{
    "groupid": 140,
    "parentid": 58,
    "usrdesc": "NIO"
},
{
    "groupid": 148,
    "parentid": 58,
    "usrdesc": "ADGB"
},
{
    "groupid": 62,
    "parentid": 1,
    "usrdesc": "OUS"
},
{
    "groupid": 136,
    "parentid": 1,
    "usrdesc": "BGE"
},
{
    "groupid": 137,
    "parentid": 136,
    "usrdesc": "PDS"
},
{
    "groupid": 138,
    "parentid": 136,
    "usrdesc": "DVE"
}
]

OUTPUT

const response = [
{
    "groupid": 1,
    "parentid": 0,
    "usrdesc": "Principal",
    "chlds": [
        {
            "groupid": 43,
            "parentid": 1,
            "usrdesc": "Opers",
            "chlds": [
                {
                    "groupid": 44,
                    "parentid": 43,
                    "usrdesc": "London",
                    "chlds": [
                        {
                            "groupid": 45,
                            "parentid": 44,
                            "usrdesc": "Sells",
                            "chlds": [
                                {
                                    "groupid": 46,
                                    "parentid": 45,
                                    "usrdesc": "grp",
                                    "chlds": [
                                        {
                                            "groupid": 89,
                                            "parentid": 46,
                                            "usrdesc": "PFG"
                                        }
                                    ]
                                }
                            ]
                        },
                        {
                            "groupid": 48,
                            "parentid": 44,
                            "usrdesc": "WEF"
                        },
                        {
                            "groupid": 49,
                            "parentid": 44,
                            "usrdesc": "API",
                            "chlds": [
                                {
                                    "groupid": 50,
                                    "parentid": 49,
                                    "usrdesc": "CTX"
                                }
                            ]
                        },
                        {
                            "groupid": 142,
                            "parentid": 44,
                            "usrdesc": "CSS"
                        }
                    ]
                }
            ]
        },
        {
            "groupid": 58,
            "parentid": 1,
            "usrdesc": "ASD",
            "chlds": [
                {
                    "groupid": 71,
                    "parentid": 58,
                    "usrdesc": "CZX"
                },
                {
                    "groupid": 106,
                    "parentid": 58,
                    "usrdesc": "RTE"
                },
                {
                    "groupid": 140,
                    "parentid": 58,
                    "usrdesc": "NIO"
                },
                {
                    "groupid": 148,
                    "parentid": 58,
                    "usrdesc": "ADGB"
                }
            ]
        },
        {
            "groupid": 62,
            "parentid": 1,
            "usrdesc": "OUS"
        },
        {
            "groupid": 136,
            "parentid": 1,
            "usrdesc": "BGE",
            "chlds": [
                {
                    "groupid": 137,
                    "parentid": 136,
                    "usrdesc": "PDS"
                },
                {
                    "groupid": 138,
                    "parentid": 136,
                    "usrdesc": "DVE"
                }
            ]
        }
    ]
}
]

This is my code

const nested = data.reduce((acc, item) => {
if (item.parentid === 0) {
  return [...acc, item];
} else {
  const parentIndex = acc.findIndex(parent => parent.groupid === item.parentid);
  const parent = acc[parentIndex];
  if (parentIndex >= 0) {
    const children = parent.children ?? [];
    return Object.assign([], acc, {
      [parentIndex]: {
        ...parent,
        children: [...children, item],
      },
    });
  }
  return acc
}
  }, []);

CodePudding user response：

For this recursion problem, I would tend to not bother with nested reduce but doing something like :

function attachChildren (item, data) {
  const children = data
    .filter(d => d.parentid === item.groupid)
    .map(d => attachChildren(d, data))

  return children.length ? { ...item, children } : item
}

console.dir(attachChildren(data[0], data), { depth: null })

Note: I've used children like in your code snippet, so you may need to adjust it to use chlds like in the output.