I have an array of regions the highest region has key: 10 and parent_id: null and I want to restructure this array to return a tree.
Regions tree should look like if the input is [10]
- Egypt
- Zone 1
- Tagamo3
- Giza
- Helwan
- Fayoum
- Zone 2
- Gesr ElSuis
- test
- Delta
- Mohandeseen
- Down Town
- Gesr ElSuis
Array:
[
{
"key": 1,
"title": "Zone 1",
"parent_id": 10
},
{
"key": 2,
"title": "Zone 2",
"parent_id": 10
},
{
"key": 3,
"title": "Tagamo3",
"parent_id": 1
},
{
"key": 4,
"title": "Gesr ElSuis",
"parent_id": 2
},
{
"key": 5,
"title": "Delta",
"parent_id": 2
},
{
"key": 6,
"title": "Mohandeseen",
"parent_id": 2
},
{
"key": 7,
"title": "Giza",
"parent_id": 1
},
{
"key": 8,
"title": "Helwan",
"parent_id": 1
},
{
"key": 9,
"title": "Down Town",
"parent_id": 2
},
{
"key": 10,
"title": "Egypt",
"parent_id": null
},
{
"key": 11,
"title": "Fayoum",
"parent_id": 1
},
{
"key": 12,
"title": "test",
"parent_id": 4
}
]
The output I want to achieve if input is [10]:
[
{
"key": 10,
"title": "Egypt",
"parent_id": null,
"children": [
{
"key": 1,
"title": "Zone 1",
"parent_id": 10,
"children": [
{
"key": 3,
"title": "Tagamo3",
"parent_id": 1,
"children": []
},
{
"key": 7,
"title": "Giza",
"parent_id": 1,
"children": []
},
{
"key": 8,
"title": "Helwan",
"parent_id": 1,
"children": []
},
{
"key": 11,
"title": "Fayoum",
"parent_id": 1,
"children": []
}
]
},
{
"key": 2,
"title": "Zone 2",
"parent_id": 10,
"children": [
{
"key": 4,
"title": "Gesr ElSuis",
"parent_id": 2,
"children": [
{
"key": 12,
"title": "test",
"parent_id": 4,
"children": []
}
]
},
{
"key": 5,
"title": "Delta",
"parent_id": 2,
"children": []
},
{
"key": 6,
"title": "Mohandeseen",
"parent_id": 2,
"children": []
},
{
"key": 9,
"title": "Down Town",
"parent_id": 2,
"children": []
}
]
}
]
}
]
Regions tree should look like if the input is [1,2]
- Zone 1
- Tagamo3
- Giza
- Helwan
- Fayoum
- Zone 2
- Gesr ElSuis
- test
- Delta
- Mohandeseen
- Down Town
- Gesr ElSuis
Regions tree should look like if the input is [1]
- Zone 1
- Tagamo3
- Giza
- Helwan
- Fayoum
CodePudding user response：
May not be the most optimized, but I gave it a try:
const arr = [{key:1,title:"Zone 1",parent_id:10},{key:2,title:"Zone 2",parent_id:10},{key:3,title:"Tagamo3",parent_id:1},{key:4,title:"Gesr ElSuis",parent_id:2},{key:5,title:"Delta",parent_id:2},{key:6,title:"Mohandeseen",parent_id:2},{key:7,title:"Giza",parent_id:1},{key:8,title:"Helwan",parent_id:1},{key:9,title:"Down Town",parent_id:2},{key:10,title:"Egypt",parent_id:null},{key:11,title:"Fayoum",parent_id:1},{key:12,title:"test",parent_id:4}];
const buildTree = key => arr.filter(x => x.parent_id === key)
.map(x => ({ ...x, children: buildTree(x.key) }));
console.log(buildTree(null));To build multiple trees, this could work:
const arr = [{key:1,title:"Zone 1",parent_id:10},{key:2,title:"Zone 2",parent_id:10},{key:3,title:"Tagamo3",parent_id:1},{key:4,title:"Gesr ElSuis",parent_id:2},{key:5,title:"Delta",parent_id:2},{key:6,title:"Mohandeseen",parent_id:2},{key:7,title:"Giza",parent_id:1},{key:8,title:"Helwan",parent_id:1},{key:9,title:"Down Town",parent_id:2},{key:10,title:"Egypt",parent_id:null},{key:11,title:"Fayoum",parent_id:1},{key:12,title:"test",parent_id:4}];
const buildNode = x => ({...x, children: buildTree(x.key)});
const buildTree = key => arr.filter(x => x.parent_id === key)
.map(buildNode);
const buildTrees = keys => arr.filter(x => keys.includes(x.key))
.map(buildNode);
console.log(buildTrees([1, 2]));CodePudding user response：
based on jcalz snippet, but requires only a single pass over the input array.
const arr = [{key:1,title:"Zone 1",parent_id:10},{key:2,title:"Zone 2",parent_id:10},{key:3,title:"Tagamo3",parent_id:1},{key:4,title:"Gesr ElSuis",parent_id:2},{key:5,title:"Delta",parent_id:2},{key:6,title:"Mohandeseen",parent_id:2},{key:7,title:"Giza",parent_id:1},{key:8,title:"Helwan",parent_id:1},{key:9,title:"Down Town",parent_id:2},{key:10,title:"Egypt",parent_id:null},{key:11,title:"Fayoum",parent_id:1},{key:12,title:"test",parent_id:4}];
/*const lookup: Record<number|"roots", Tree[]> = { roots: [] };*/
const lookup = { roots: [] };
for (const item of arr) {
// get or create the "children" array for my parent.
// parent may not be known yet, but I'm already collecting its children, my siblings.
const siblings = lookup[item.parent_id ?? "roots"] ??= [];
// add myself to that children array.
siblings.push({
...item,
// get or create my children array.
children: lookup[item.key] ??= []
});
}
// it's up to you to handle `lookup.roots.length !== 1`
console.log(lookup.roots);.as-console-wrapper{top:0;max-height:100%!important}