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I need to create a new array from another with the condition:
for example from an array
mainArr: [
{
"id":1,
"name":"root"
},
{
"id":2,
"parentId":1,
"name":"2"
},
{
"id":148,
"parentId":2,
"name":"3"
},
{
"id":151,
"parentId":148,
"name":"4"
},
{
"id":152,
"parentId":151,
"name":"5"
}
]
I need to make an array ['1','2','148','151'] which means the path from "parentId"'s to "id":152 - (argument for this function).
I think main logic can be like this:
const parentsArr = [];
mainArr.forEach((item) => {
if (item.id === id) {
parentsArr.unshift(`${item.parentId}`);
}
and the result {item.parentId} should be used to iterate again. But I don't understand how to do it...
You could use a recursive function for this. First you can transform your array to a Map, where each id from each object points to its object. Doing this allows you to .get() the object with a given id efficiently. For each object, you can get the parentId, and if it is defined, rerun your traverse() object again searching for the parent id. When you can no longer find a parentid, then you're at the root, meaning you can return an empty array to signify no parentid object exist:
const arr = [{"id":1,"name":"root"},{"id":2,"parentId":1,"name":"2"},{"id":148,"parentId":2,"name":"3"},{"id":151,"parentId":148,"name":"4"},{"id":152,"parentId":151,"name":"5"}];
const transform = arr => new Map(arr.map((o) => [o.id, o]));
const traverse = (map, id) => {
const startObj = map.get(+id);
if("parentId" in startObj)
return [...traverse(map, startObj.parentId), startObj.parentId];
else
return [];
}
console.log(traverse(transform(arr), "152"));
If you want to include "152" in the result, you can change your recursive function to use the id argument, and change the base-case to return [id] (note that the + in front of id is used to convert it to a number if it is a string):
const arr = [{"id":1,"name":"root"},{"id":2,"parentId":1,"name":"2"},{"id":148,"parentId":2,"name":"3"},{"id":151,"parentId":148,"name":"4"},{"id":152,"parentId":151,"name":"5"}];
const transform = arr => new Map(arr.map((o) => [o.id, o]));
const traverse = (map, id) => {
const startObj = map.get(+id);
if("parentId" in startObj)
return [...traverse(map, startObj.parentId), +id];
else
return [+id];
}
console.log(traverse(transform(arr), "152"));
I would start by indexing the data by id using reduce
var byId = data.reduce( (acc,i) => {
acc[i.id] = i
return acc;
},{});
And then just go through using a loop and pushing the id to a result array
var item = byId[input];
var result = []
while(item.parentId) {
result.push(item.parentId)
item = byId[item.parentId];
}
Live example:
const input = 152;
const data = [ { "id":1, "name":"root" }, { "id":2, "parentId":1, "name":"2" }, { "id":148, "parentId":2, "name":"3" }, { "id":151, "parentId":148, "name":"4" }, { "id":152, "parentId":151, "name":"5" } ]
var byId = data.reduce( (acc,i) => {
acc[i.id] = i
return acc;
},{});
var item = byId[input];
var result = []
while(item.parentId) {
result.push(item.parentId)
item = byId[item.parentId];
}
console.log(result.reverse());
Try changing this line
parentsArr.unshift(`${item.parentId}`);
To this
parentsArr.push(`${item.parentId}`);
Then try
console.log(parentsArr);
This is what I ended up with. Basically a mix of Janek and Nicks answers. It's just 2 steps:
transform code to a map.
extract the ancester_id's with a little function
let data = [
{"id":1,"name":"root"},
{"id":2,"parentId":1,"name":"2"},
{"id":148,"parentId":2,"name":"3"},
{"id":151,"parentId":148,"name":"4"},
{"id":152,"parentId":151,"name":"5"}
];
data = data.reduce( (acc, value) => {
// could optionally filter out the id here
return acc.set(value.id, value)
}, new Map());
function extract_ancestors( data, id ) {
let result = [];
while( data.get( id ).parentId ) {
id = data.get( id ).parentId;
result.push(id)
}
return result;
}
// some visual tests
console.log( extract_ancestors( data, 152 ) );
console.log( extract_ancestors( data, 148 ) );
console.log( extract_ancestors( data, 1 ) );
PS: My OOP tendencies start to itch so much from this haha.
I have a json response that looks like the image below. I want to get all dates from the json and store in an array.
function buyOption(){
var ticker = document.getElementById('ticker').value;
fetch("https://stock-and-options-trading-data-provider.p.rapidapi.com/options/JPM", {
.then(response => response.json())
.then(data => {
dataset = data;
console.log(dataset['options'])
loadTable()
})
.catch(err => {
console.log(err);
});
function loadTable(){
expiration_dates = []
dates = dataset['options']
// console.log(JSON.parse(dates))
var keys = [];
for(var k in dates) keys.push(k);
console.log(keys)// returns ["0","1","2",3","5",6","9","10","11"]
console.log(dates[0].value) // returns undefined
}
}
goal is to have expiration_dates = ["2020-08-21","2020-08-28"]
You can try this. This will give you only the expiration dates.
var obj = {
"options": [{
"10-2-2001": "",
"someOtherProp": ""
}, {
"20-2-2001": "",
"someOtherProp": ""
}]
}
var expDates = obj.options.map(o=>Object.keys(o)[0])
console.log(expDates)
Refs:
Array.map()
Object.keys()
Try this
let result = dataSet.options.map(x => Object.keys(x));
console.log(result.flat(1))
A simple array map should do the trick and use Object.keys() array to get first key from each object in your data array
const dates = dataset['options'].map(o => Object.keys(o)[0])
console.log(dates)
<script>
const dataset = {
options: [{
'2013-12-22': {
puts: [],
calls: []
}},
{'2013-02-15': {
puts: [],
calls: []
}},
{ '2018-01-01': {
puts: [],
calls: []
}}
]
}
</script>
Something like
const options=dates.options.map(o=>
Object.keys(o).filter(k=>k.match(/^2\d{3}-\d{2}-\d{2}$/))[0]);
The idea is to loop over all options, get all keys for each of the objects and filter out the keys matching the Regexp, which is a date format, starting with 2. From the filtered keys-array I am only interested in the first element ([0]).
for(k in dates) {
keys.push((v=>{
for(let i in v) return i;
})(dates[k]));
}
Try it
My array comes like this
var data=[{PRODUCT : P1}, {PRODUCT: P2}]
I wantt to convert this into [P1, P2].
Sometimes my array comes like this
var data=[{ITEM: I1, QUANTITY:1}, {ITEM: I2, QUANTITY:2}]
I wantt to convert this into [I1, I2].
so can we make a common function, where I just want to extract particular value of array and make a new array.
p.s. Thank you in advance
I tried to write the logic like this:
data.map((d, index) => { var result= [];
result.includes(d[0]); })
but it,s not dynamic
You could define a function which will always get the first value of the first object key, this should satisfy your needs based on the above
var data1 = [{
ITEM: 'I1',
QUANTITY: 1
}, {
ITEM: 'I2',
QUANTITY: 2
}]
var data2 = [{
PRODUCT: 'P1'
}, {
PRODUCT: ' P2'
}]
function getArrayOfValues(list) {
return list.reduce((acc, x) => {
const firstValue = Object.values(x)[0];
acc.push(firstValue)
return acc;
}, [])
}
const result1 = getArrayOfValues(data1)
console.log(result1)
const result2 = getArrayOfValues(data2)
console.log(result2)
function getProductOrItem(list) {
return list.reduce((accumulator, obj) => {
if (obj.PRODUCT) {
accumulator.push(obj.PRODUCT);
} else if (obj.ITEM) {
accumulator.push(obj.ITEM);
}
return accumulator;
}, [])
}
you can iterate through your array with map() method and inside it extract the value of a first entity of an object in your array and simply get a new array with all values:
const data1 =[{PRODUCT : 'P1'}, {PRODUCT: 'P2'}]
const data2 = [{ITEM: 'I1', QUANTITY: 1}, {ITEM: 'I2', QUANTITY: 2 }]
const transformValuesOfArray = (arrayToTransform) =>
arrayToTransform.map(value => {
const firstObjectValue = Object.values(value)[0]
return firstObjectValue
})
console.log(transformValuesOfArray(data1))
console.log(transformValuesOfArray(data2))
I have an array like
[
"parent1|child1|subChild1",
"parent1|child1|subChild2",
"parent|child2|subChild1",
"parent1|child2|subChild2",
"parent2|child1|subChild1",
"parent2|child1|subChild2",
"parent2|child2|subChild1",
.
.
.
]
Wherein my first string before | is the parent and the second string before | is the child and the third string after the second | is the subchild
How can I convert this array into an object like
[
{
"id": "parent1",
"children":[
{
"id": "child1",
"children":[
{
"id": "subChild1"
}
]
}
]
}
]
Parent -> child -> subchild object
Based on Sebastian's answer I tried below using typescript
private genTree(row) {
let self = this;
if (!row) {
return;
}
const [parent, ...children] = row.split('|');
if (!children || children.length === 0) {
return [{
id: parent,
children: []
}];
}
return [{
id: parent,
children: self.genTree(children.join('|'))
}];
}
private mergeDeep(children) {
let self = this;
const res = children.reduce((result, curr) => {
const entry = curr;
const existing = result.find((e) => e.id === entry.id);
if (existing) {
existing.children = [].concat(existing.children, entry.children);
} else {
result.push(entry);
}
return result;
}, []);
for (let i = 0; i < res.length; i++) {
const entry = res[i];
if (entry.children && entry.children.length > 0) {
entry.children = self.mergeDeep(entry.children);
}
};
return res;
}
private constructTree(statKeyNames){
let self = this;
const res = this.mergeDeep(statKeyNames.map(self.genTree).map(([e]) => e));
console.log(res);
}
but this gives me:
Cannot read property 'genTree' of undefined" error
Update:
As per Sebastian's comment changed self.genTree to this.genTree.bind(this) and it worked without any issues
You could use a mapper object which maps each object to it's unique path (You could map the object with each id, but id is not unique here). Then reduce each partial item in the array. Set the root object as the initialValue. The accumulator will be the parent object for the current item. Return the current object in each iteration.
const input = [
"parent1|child1|subChild1",
"parent1|child1|subChild2",
"parent1|child2|subChild1",
"parent1|child2|subChild2",
"parent2|child1|subChild1",
"parent2|child1|subChild2",
"parent2|child2|subChild1"
],
mapper = {},
root = { children: [] }
for (const str of input) {
let splits = str.split('|'),
path = '';
splits.reduce((parent, id, i) => {
path += `${id}|`;
if (!mapper[path]) {
const o = { id };
mapper[path] = o; // set the new object with unique path
parent.children = parent.children || [];
parent.children.push(o)
}
return mapper[path];
}, root)
}
console.log(root.children)
You have to use recursion for that. Take a look here:
const arr = [
"parent1|child1|subChild1",
"parent1|child1|subChild2",
"parent|child2|subChild1",
"parent1|child2|subChild2",
"parent2|child1|subChild1",
"parent2|child1|subChild2",
"parent2|child2|subChild1"
];
function genTree(row) {
const [parent, ...children] = row.split('|');
if (!children || children.length === 0) {
return [{
id: parent,
children: []
}];
}
return [{
id: parent,
children: genTree(children.join('|'))
}];
};
function mergeDeep(children) {
const res = children.reduce((result, curr) => {
const entry = curr;
const existing = result.find((e) => e.id === entry.id);
if (existing) {
existing.children = [].concat(existing.children, entry.children);
} else {
result.push(entry);
}
return result;
}, []);
for (let i = 0; i < res.length; i++) {
const entry = res[i];
if (entry.children && entry.children.length > 0) {
entry.children = mergeDeep(entry.children);
}
};
return res;
}
const res = mergeDeep(arr.map(genTree).map(([e]) => e));
console.log(JSON.stringify(res, false, 2));
I used two helpers here: genTree(row) which recursively generates a simple tree from each row, and mergeDeep(children) which reduces the first-level trees in the result of arr.map(genTree).map(([e]) => e), and then iterates over the array and recursively does the same thing to all children of each entry.
I have a JSON array of the following type:
"team": [
{
"paid": {
"refugee": 2018,
"local": 29000,
"international": 12000
}
},
{
"unpaid": {
"refugee": 2019,
"local": 39000,
"international": 19000
}
}
]
I would like to push the values of matching keys into an array, so that I end up with the following new arrays:
var refugees = [2018, 2019]
var local = [29000, 39000]
var international = [12000, 19000]
and so on..
What would be a simple method of doing this? I have succesfully used jQuery in the past for this but need a Javascript only solution:
$.each(team, function (i, v) {
var teams = v;
console.log(teams);
$.each(v, function (i, v) {
refugees.push(v.refugee);
local.push(v.local);
international.push(v.international);
});
});
Try this
var a={"team" : [
{
"paid": {
"refugee": 2018,
"local": 29000,
"international": 12000
}
},
{
"unpaid": {
"refugee": 2019,
"local": 39000,
"international": 19000
}
}
]}
var refugee=[];
var local=[];
var international=[];
a.team.map((e)=>{
if(e.paid)
{
refugee.push(e.paid.refugee);
local.push(e.paid.local);
international.push(e.paid.international)
}
else
{
refugee.push(e.unpaid.refugee);
local.push(e.unpaid.local);
international.push(e.unpaid.international)
}
})
console.log(local)
console.log(international)
console.log(refugee)
You can use reduce.
So here the idea is we are taking a the keys and mapping it to output object. we keep checking if the key is already their in output object we push the value to that particular key and if not we add a new property with value.
let obj = {"team":[{"paid":{"refugee":2018,"local":29000,"international":12000}},{"unpaid":{"refugee":2019,"local":39000,"international":19000}}]}
let op = obj.team.reduce((output,current)=>{
let temp = Object.values(current)[0]
let values = Object.keys(temp)
values.forEach(ele=>{
if(output[ele]){
output[ele].push(temp[ele])
} else {
output[ele] = [temp[ele]]
}
})
return output;
}, {})
console.log(op)
Something like this would work if you wanted a few one-liners:
let local = team.reduce((acc, item) => acc.concat(Object.values(item).map(val => val.local)), []);
let refugee = team.reduce((acc, item) => acc.concat(Object.values(item).map(val => val.refugee)), []);
Use Array#reduce, Object#values, Object#entries, spread syntax, destructuring and Map
const data={"team":[{"paid":{"refugee":2018,"local":29000,"international":12000}},{"unpaid":{"refugee":2019,"local":39000,"international":19000}}]}
const res = data.team.reduce((a,c)=>{
Object.values(c)
.map(Object.entries)
.flat()
.forEach(([k,v])=>{
const arr = a.get(k) || [];
arr.push(v)
a.set(k, arr);
})
return a;
}, new Map())
//get all
console.log([...res.values()]);
//get by type
console.log(res.get('refugee'));
console.log(res.get('local'));
console.log(res.get('international'));