I have a recursive object of the structure:
const obj = {
name: 'entity-0',
children: [{
name: 'entity-0-0',
children: []
}, {
name: 'entity-0-1',
children: [{
name: 'entity-1-0',
children: []
}]
}]
}
And I'm currently converting it to a flat array like this:
const arr = [];
function convertObjToArr(obj, level, parent) {
arr.push({ name: obj.name, parent: parent?.name, level });
obj.children.forEach(v => this.convertObjToArr(v, level + 1, obj));
}
convertObjToArr(obj, 0);
This results in array that looks like this:
[
{ name: 'entity-0', level: 0 },
{ name: 'entity-0-0', parent: 'entity-0', level: 1 },
{ name: 'entity-0-1', parent: 'entity-0', level: 1 },
{ name: 'entity-1-0', parent: 'entity-0-1', level: 2}
]
What I now need to do is reverse the process. Where I give the generated arr as the input and get obj as the output. Is this possible? How would I do this?
This is as far as I've gotten:
function convertArrToObj(iArr) {
for(let i = 0; i < iArr.length; i++) {
if(!iArr[i].parent) newObj = { ...iArr[i], children: [] };
else {
// this should somehow find iArr[i].parent and insert itself into its children array
}
}
}
But as you can see, it's incomplete and I'm pretty sure it's not gonna be recursive, so if it's more than 1 layer deep it won't work, I don't think.
You could take a single loop and build a new structure.
const
getTree = (data, root) => {
const t = {};
data.forEach(({ name, parent }) =>
((t[parent] ??= {}).children ??= []).push(Object.assign(t[name] ??= {}, { name }))
);
return t[root].children;
},
data = [{ name: "entity-0", parent: undefined, level: 0 }, { name: "entity-0-0", parent: "entity-0", level: 1 }, { name: "entity-0-1", parent: "entity-0", level: 1 }, { name: "entity-1-0", parent: "entity-0-1", level: 2 }],
tree = getTree(data);
console.log(tree);.as-console-wrapper { max-height: 100% !important; top: 0; }This might work.
If there is a single root, take the first element in the result array.
const arr = [
{ name: 'entity-0', level: 0 },
{ name: 'entity-0-0', parent: 'entity-0', level: 1 },
{ name: 'entity-0-1', parent: 'entity-0', level: 1 },
{ name: 'entity-1-0', parent: 'entity-0-1', level: 2}
];
const convertArrToObj = (arr, parent) => {
return arr.filter(item => item.parent === parent)
.reduce((acc, item) => {
acc.push({name: item.name, children: convertArrToObj(arr, item.name)});
return acc;
}, []);
};
const result = convertArrToObj(arr);
console.log(result);
// using map is simpler, advised by Nick Parsons
const convertArrToObj2 = (arr, parent) => {
return arr.filter(item => item.parent === parent)
.map(item => ({name: item.name, children: convertArrToObj2(arr, item.name)}));
};
console.log(convertArrToObj2(arr));