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Filtering and storing and finding parent child relationship in elements of array [duplicate]

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How to find a node in a tree with JavaScript
(19 answers)
Javascript - Find path to object reference in nested object
(3 answers)
Closed 1 year ago.
I am working on an angular application. My data is as follows
data= [
{
"id": 2,
"name": "Jamie",
"objectId": 200,
"parentId": null,
"children": [
{
"id": 98,
"name": "Rose",
"objectId": 100,
"parentId": 200,
"children": [
{
"id": 1212,
"name": "julie",
"objectId": 500,
"parentId": 100,
"children": []
}
]
},
{
"id": 67,
"name": "Kosy",
"objectId": 700,
"parentId": 200,
"children": []
}
]
}
]
I will be having input id and name. Suppose in my method I get id as 1212 and name as "julie". So I want to go to that node whose id is 1212 and name is equal to
"julie", once this condition is met. I need to check parentId in children is equal to objectId in parent till parentId becomes null.
If parent id becomes null then it is considered as last node and then I want to have my data in the array in following format. For id 1212 and name
"julie" resultArray is
resultArray = ["Jamie/Rose/Julie "]. Data starting from parent to children separated by slash.
Another example is if I get id as 67 and name "Kosy". then result array will be
resultArray = ["Jamie/Kosy"]
As parentId of Kosy is 200 and ObjectId of Jamie is 200, which indicate that Jamie is parent of Kosy, that's why data should look like this. want to have dynamic code as at run time data can be huge but structure and logic will be same as mentioned above
How can I do this

I wrote the code for this problem. Please try the following code. This is one of the typical tree-search problem. One point what sets it apart from traditional tree search is checking its parent. That was easily solved here.
const data = [
{
"id": 2,
"name": "Jamie",
"objectId": 200,
"parentId": null,
"children": [
{
"id": 98,
"name": "Rose",
"objectId": 100,
"parentId": 200,
"children": [
{
"id": 1212,
"name": "julie",
"objectId": 500,
"parentId": 100,
"children": []
}
]
},
{
"id": 67,
"name": "Kosy",
"objectId": 700,
"parentId": 200,
"children": []
}
]
}
];
// function that search the target in a node(not a array)
// In order for this function to return true, id comparison from the final node to this node should be passed as well
const findInNode = (node, id, name, output) => {
if (node.name === name && node.id === id) { // self test
return true;
} else {
const children = node.children;
if (!children) return false;
// find in children
for (let child of children) {
// output.paths is the current search path
output.paths.push(child.name);
if (findInNode(child, id, name, output)) {
// if found, compare the self objectId and child's parentId
return child.parentId === node.objectId;
}
output.paths.pop();
}
}
}
// function that search the target in an array, for use at the top-most level
const findInArray = (nodes, id, name, output) => {
for (let node of nodes) {
output.paths.push(node.name);
if (findInNode(node, id, name, output)) {
if (!node.parentId) {
output.found = true;
break;
}
}
output.paths.pop();
}
}
output = { paths: [], found: false };
findInArray(data, 1212, 'julie', output);
console.log(output.found);
console.log(output.paths.join('/'));

Reverse Traverse a hierarchy

I have a hierarchy of objects that contain the parent ID on them. I am adding the parentId to the child object as I parse the json object like this.
public static fromJson(json: any): Ancestry | Ancestry[] {
if (Array.isArray(json)) {
return json.map(Ancestry.fromJson) as Ancestry[];
}
const result = new Ancestry();
const { parents } = json;
parents.forEach(parent => {
parent.parentId = json.id;
});
json.parents = Parent.fromJson(parents);
Object.assign(result, json);
return result;
}
Any thoughts on how to pull out the ancestors if I have a grandchild.id?
The data is on mockaroo curl (Ancestries.json)
As an example, with the following json and a grandchild.id = 5, I would create and array with the follow IDs
['5', '0723', '133', '1']
[{
"id": "1",
"name": "Deer, spotted",
"parents": [
{
"id": "133",
"name": "Jaime Coldrick",
"children": [
{
"id": "0723",
"name": "Ardys Kurten",
"grandchildren": [
{
"id": "384",
"name": "Madelle Bauman"
},
{
"id": "0576",
"name": "Pincas Maas"
},
{
"id": "5",
"name": "Corrie Beacock"
}
]
},

There is perhaps very many ways to solve this, but in my opinion the easiest way is to simply do a search in the data structure and store the IDs in inverse order of when you find them. This way the output is what you are after.
You could also just reverse the ordering of a different approach.
I would like to note that the json-structure is a bit weird. I would have expected it to simply have nested children arrays, and not have them renamed parent, children, and grandchildren.
let data = [{
"id": "1",
"name": "Deer, spotted",
"parents": [
{
"id": "133",
"name": "Jaime Coldrick",
"children": [
{
"id": "0723",
"name": "Ardys Kurten",
"grandchildren": [
{
"id": "384",
"name": "Madelle Bauman"
},
{
"id": "0576",
"name": "Pincas Maas"
},
{
"id": "5",
"name": "Corrie Beacock"
}
]
}]
}]
}]
const expectedResults = ['5', '0723', '133', '1']
function traverseInverseResults(inputId, childArray) {
if(!childArray){ return }
for (const parent of childArray) {
if(parent.id === inputId){
return [parent.id]
} else {
let res = traverseInverseResults(inputId, parent.parents || parent.children || parent.grandchildren) // This part is a bit hacky, simply to accommodate the strange JSON structure.
if(res) {
res.push(parent.id)
return res
}
}
}
return
}
let result = traverseInverseResults('5', data)
console.log('results', result)
console.log('Got expected results?', expectedResults.length === result.length && expectedResults.every(function(value, index) { return value === result[index]}))

Merging an array of objects without overwriting

I am currently with some JSON, which has to be structured in a tree-like hierarchy. The depth of the hierarchy varies a lot, and is therefor unknown.
As it is right now, I have achieved to get an array of objects. Example is below.
[
{
"name": "level1",
"collapsed": true,
"children": [
{
"name": "Level 1 item here",
"id": 360082134191
}
]
},
{
"name": "level1",
"collapsed": true,
"children": [
{
"name": "level2",
"collapsed": true,
"children": [
{
"name": "Level 2 item here",
"id": 360082134751
}
]
}
]
},
{
"name": "level1",
"collapsed": true,
"children": [
{
"name": "Another level 1 item",
"id": 360082262772
}
]
}
]
What I want to achieve is these objects to be merged, without overwriting or replacing anything. Listed below is an example of how I want the data formatted:
[
{
"name": "level1",
"collapsed": true,
"children": [
{
"name": "level2",
"collapsed": true,
"children": [
{
"name": "Level 2 item here",
"id": 360082134751
}
]
},
{
"name": "Level 1 item here",
"id": 360082134191
},
{
"name": "Another level 1 item",
"id": 360082262772
}
]
}
]
How would I achieve this with JavaScript? No libraries is preferred, ES6 can be used though.
Edit:
It is important that the output is an array, since items without children can appear at the root.

I am assuming you need a little help on working with the data. There could be multiple ways to achieve this, here is how would I do.
// data => supplied data
const result = data.reduce ((acc, item) => {
// if acc array already contains an object with same name,
// as current element [item], merfe the children
let existingItem;
// Using a for loop here to create a reference to the
// existing item, so it'd update this item when childrens
// will be merged.
for (let index = 0; index < acc.length; index ++) {
if (acc[index].name === item.name) {
existingItem = acc[index];
break;
}
}
// if existingItem exists, merge children of
// existing item and current item.
// else push it into the accumulator
if (existingItem) {
existingItem.children = existingItem.children.concat(item.children);
} else {
acc.push (item);
}
return acc;
}, []);

I'm assuming you want to group based on the name property in the level 1 object. You could do a simple reduce and Object.values like this:
const input = [{"name":"level1","collapsed":true,"children":[{"name":"Level 1 item here","id":360082134191}]},{"name":"level1","collapsed":true,"children":[{"name":"level2","collapsed":true,"children":[{"name":"Level 2 item here","id":360082134751}]}]},{"name":"level1","collapsed":true,"children":[{"name":"Another level 1 item","id":360082262772}]}]
const merged = input.reduce((r,{name, collapsed, children}) =>{
r[name] = r[name] || {name, collapsed, children:[]};
r[name]["children"].push(...children)
return r;
}, {})
const final = Object.values(merged);
console.log(final)
You could do the whole thing in one line:
const input = [{"name":"level1","collapsed":true,"children":[{"name":"Level 1 item here","id":360082134191}]},{"name":"level1","collapsed":true,"children":[{"name":"level2","collapsed":true,"children":[{"name":"Level 2 item here","id":360082134751}]}]},{"name":"level1","collapsed":true,"children":[{"name":"Another level 1 item","id":360082262772}]}]
const output = Object.values(input.reduce((r,{name,collapsed,children}) => (
(r[name] = r[name] || {name,collapsed,children: []})["children"].push(...children), r), {}))
console.log(output)

cannot update an array of elements via a 2d iteration

I have two arrays of object, the first array (printerChart, around 80 elements) is made of the following type of objects:
[{
printerBrand: 'Mutoh',
printerModel: 'VJ 1204G',
headsBrand: 'Epson',
headType: '',
compatibilty: [
'EDX',
'DT8',
'DT8-Pro',
'ECH',
],
},
....
]
The second array (items, around 500 elements) is made of the following type of objects:
[
{
"customData": {
"brand": {
"value": {
"type": "string",
"content": "hp"
},
"key": "brand"
},
"printer": {
"value": {
"type": "string",
"content": "c4280"
},
"key": "printer"
}
},
"name": "DT8 XLXL",
"image": {
"id": "zLaDHrgbarhFSnXAK",
"url": "https://xxxxxxx.net/images/xxxxxx.jpg"
},
"brandId": "xxxxx",
"companyId": "xxxx",
"createdAt": "2018-03-26T14:39:47.326Z",
"updatedAt": "2018-04-09T14:31:38.169Z",
"points": 60,
"id": "dq2Zezwm4nHr8FhEN"
},
...
]
What I want to do is to iterate via the second array and, if the part of the name of an item (i.e. DT8) is included in an element of the array 'compatibility' of the first array, I would like to include a new properties to it from the element of the first array: printerBrand. I have tried but somehow the iteration doesn't take place correctly. This is what I tried:
items.forEach((item) => {
printerChart.forEach((printer) => {
if (printer.compatibilty.some(compatibleElem => (
item.name.includes(compatibleElem)))) {
item.printerBrand = printer.printerBrand;
} else {
item.printerBrand = '';
}
});
});
What am I doing wrong?

You do
items.items.forEach(...)
Shouldn't you be doing
items.forEach(...)
?

I suggest to initialize item.printerBrand with an empty string and use a nested approach of some for getting a brand and to exit the loops, if found.
This prevents to get an empty string even if there is a brand to assign.
items.forEach((item) => {
item.printerBrand = '';
printerChart.some(printer => {
if (printer.compatibilty.some(compatibleElem => item.name.includes(compatibleElem))) {
item.printerBrand = printer.printerBrand;
return true;
}
});
});

Rename json keys iterative

I got a very simple json but in each block I got something like this.
var json = {
"name": "blabla"
"Children": [{
"name": "something"
"Children": [{ ..... }]
}
And so on. I don't know how many children there are inside each children recursively.
var keys = Object.keys(json);
for (var j = 0; j < keys.length; j++) {
var key = keys[j];
var value = json[key];
delete json[key];
key = key.replace("Children", "children");
json[key] = value;
}
And now I want to replace all "Children" keys with lowercase "children". The following code only works for the first depth. How can I do this recursively?

It looks the input structure is pretty well-defined, so you could simply create a recursive function like this:
function transform(node) {
return {
name: node.name,
children: node.Children.map(transform)
};
}
var json = {
"name": "a",
"Children": [{
"name": "b",
"Children": [{
"name": "c",
"Children": []
}, {
"name": "d",
"Children": []
}]
}, {
"name": "e",
"Children": []
}]
};
console.log(transform(json));

A possible solution:
var s = JSON.stringify(json);
var t = s.replace(/"Children"/g, '"children"');
var newJson = JSON.parse(t);
Pros: This solution is very simple, being just three lines.
Cons: There is a potential unwanted side-effect, consider:
var json = {
"name": "blabla",
"Children": [{
"name": "something",
"Children": [{ ..... }]
}],
"favouriteWords": ["Children","Pets","Cakes"]
}
The solution replaces all instances of "Children", so the entry in the favouriteWords array would also be replaced, despite not being a property name. If there is no chance of the word appearing anywhere else other than as the property name, then this is not an issue, but worth raising just in case.

Here is a function that can do it recursivly:
function convertKey(obj) {
for (objKey in obj)
{
if (Array.isArray(obj[objKey])) {
convertKey[objKey].forEach(x => {
convertKey(x);
});
}
if (objKey === "Children") {
obj.children = obj.Children;
delete obj.Children;
}
}
}
And here is a more generic way for doing this:
function convertKey(obj, oldKey, newKey) {
for (objKey in obj)
{
if (Array.isArray(obj[objKey])) {
obj[objKey].forEach(objInArr => {
convertKey(objInArr);
});
}
if (objKey === oldKey) {
obj[newKey] = obj[oldKey];
delete obj[oldKey];
}
}
}
convertKey(json, "Children", "children");

Both the accepted answer, and #Tamas answer have slight issues.
With #Bardy's answer like he points out, there is the issue if any of your values's had the word Children it would cause problems.
With #Tamas, one issue is that any other properties apart from name & children get dropped. Also it assumes a Children property. And what if the children property is already children and not Children.
Using a slightly modified version of #Tamas, this should avoid the pitfalls.
function transform(node) {
if (node.Children) node.children = node.Children;
if (node.children) node.children = node.children.map(transform);
delete node.Children;
return node;
}
var json = {
"name": "a",
"Children": [{
"age": 13,
"name": "b",
"Children": [{
"name": "Mr Bob Chilren",
"Children": []
}, {
"name": "d",
"age": 33, //other props keep
"children": [{
"name": "already lowecased",
"age": 44,
"Children": [{
"name": "now back to upercased",
"age": 99
}]
}] //what if were alrady lowercased?
}]
}, {
"name": "e",
//"Children": [] //what if we have no children
}]
};
console.log(transform(json));