Multidemisional array

Question

i am trying to create a multidimensional array from a flat array. but i somehow i can not figure it out.

I manage it to get it 1lvl deep but can not figure out how to go all the way: example :

[
  { id: 'cG9zdDoyODI=', parentId: null, children: [] },
  { id: 'cG9zdDoyODM=', parentId: null, children: [] },
  { id: 'cG9zdDoyODc=', parentId: null, children: [] },
  { id: 'cG9zdDoyODY=', parentId: 'cG9zdDoyODc=', children: [] },
  { id: 'cG9zdDozMDE=', parentId: 'cG9zdDoyODY=', children: [] },
  { id: 'cG9zdDozMDI=', parentId: 'cG9zdDozMDE=', children: [] },
  { id: 'cG9zdDoyODQ=', parentId: 'cG9zdDoyODc=', children: [] },
  { id: 'cG9zdDoyODU=', parentId: 'cG9zdDoyODc=', children: [] } 
]

i am trying to place each object that has a parent into the parents children array.

all the help is welcome, thanks in advance

also: [Building tree array of objects from flat array of objects](https://stackoverflow.com/questions/46847573/building-tree-array-of-objects-from-flat-array-of-objects) — pilchard, Jul 17 '22 at 10:37

score -1 · Answer 1 · answered Jul 17 '22 at 10:40

If I understood that good, you wnat to do this:

const data = [
  { id: 'cG9zdDoyODI=', parentId: null, children: [] },
  { id: 'cG9zdDoyODM=', parentId: null, children: [] },
  { id: 'cG9zdDoyODc=', parentId: null, children: [] },
  { id: 'cG9zdDoyODY=', parentId: 'cG9zdDoyODc=', children: [] },
  { id: 'cG9zdDozMDE=', parentId: 'cG9zdDoyODY=', children: [] },
  { id: 'cG9zdDozMDI=', parentId: 'cG9zdDozMDE=', children: [] },
  { id: 'cG9zdDoyODQ=', parentId: 'cG9zdDoyODc=', children: [] },
  { id: 'cG9zdDoyODU=', parentId: 'cG9zdDoyODc=', children: [] } 
];

data.forEach(parent=>data.find(elem=>elem.parentId===parent.id && parent.children.push(elem)));

console.log(data);

score -1 · Answer 2 · answered Jul 17 '22 at 10:46

let arr = [
  { id: 'cG9zdDoyODI=', parentId: null, children: [] },
  { id: 'cG9zdDoyODM=', parentId: null, children: [] },
  { id: 'cG9zdDoyODc=', parentId: null, children: [] },
  { id: 'cG9zdDoyODY=', parentId: 'cG9zdDoyODc=', children: [] },
  { id: 'cG9zdDozMDE=', parentId: 'cG9zdDoyODY=', children: [] },
  { id: 'cG9zdDozMDI=', parentId: 'cG9zdDozMDE=', children: [] },
  { id: 'cG9zdDoyODQ=', parentId: 'cG9zdDoyODc=', children: [] },
  { id: 'cG9zdDoyODU=', parentId: 'cG9zdDoyODc=', children: [] } 
];

let parents = arr.filter(elem => elem.parentId === null); // filtered out parents

parents.map(elem => {
    arr.forEach(child => {
        if (elem.id === child.parentId) { // matching children by id
            elem.children.push(child);    // pushing children into parents
        }
    });
});

Multidemisional array

2 Answers2