How can I check duplicate and remove object in array object? [duplicate] - reactjs

Question

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How can I access and process nested objects, arrays, or JSON?
(31 answers)
Closed 4 months ago.
How can I find duplicate and remove object have id: 3 and just keep id: 3 in children of id: 2 ?
I have one array object like this:
const data = [
{
"id": 1,
"name": ABC,
"parentID": null,
"children": [
{
"id": 2,
"name": ASD,
"parentID": 1,
"children": [
{
"id": 3,
"name": AS,
"parentID": 2,
"children": []
}
]
}
]
},
{
"id": 3,
"name": AS,
"parentID": 2,
"children": []
},
{
"id": 4,
"name": ASC,
"parentID": null,
"children": []
}
]
I want to write a function for search and remove object id 3, Can I do that by recursive ?
Output:
const data = [
{
"id": 1,
"name": ABC,
"parentID": null,
"children": [
{
"id": 2,
"name": ASD,
"parentID": 1,
"children": [
{
"id": 3,
"name": AS,
"parentID": 2,
"children": []
}
]
}
]
},
{
"id": 4,
"name": ASC,
"parentID": null,
"children": []
}
]
Do you any idea for this issues ?
Thanks for your help 🥰

Answer 1

A simple iterative recursion should resolve this problem. You have to store a list of unique ids that represents each item in the data tree, and use these keys to check if such an item has been traversed or not.
type DataType = {
id: number;
name: string;
parentID: number | null;
children: DataType[];
};
function filterRecursive(collection: DataType[], keys: Record<number, true> = {}) {
const result: DataType[] = [];
for(const item of collection) {
if(item.id in keys === false) {
keys[item.id] = true;
result.push({
...item,
children: filterRecursive(item.children, keys)
});
}
}
return result;
}
const result = filterRecursive(data);
.as-console-wrapper {
top: 0 !important;
max-height: 100% !important;
}
<script src="https://unpkg.com/#babel/standalone#7.18.13/babel.min.js"></script>
<script type="text/babel" data-type="module" data-presets="typescript">
type DataType = {
id: number;
name: string;
parentID: number | null;
children: DataType[];
};
const data = [
{
"id": 1,
"name": 'ABC',
"parentID": null,
"children": [
{
"id": 2,
"name": 'ASD',
"parentID": 1,
"children": [
{
"id": 3,
"name": 'AS',
"parentID": 2,
"children": []
}
]
}
]
},
{
"id": 3,
"name": 'AS',
"parentID": 2,
"children": []
},
{
"id": 4,
"name": 'ASC',
"parentID": null,
"children": []
}
];
function filterRecursive(collection: DataType[], keys: Record<number, true> = {}) {
const result: DataType[] = [];
for(const item of collection) {
if(item.id in keys === false) {
keys[item.id] = true;
result.push({
...item,
children: filterRecursive(item.children, keys)
});
}
}
return result;
}
const result = filterRecursive(data);
console.log(JSON.stringify(result, null, 4));
</script>