Develop Reference

Loop through an array of objects and update parent object count if child object exists

I am using Angular 13 and I have an array of objects like this:
[{
"name": "Operating System",
"checkedCount": 0,
"children": [{
"name": "Linux",
"value": "Redhat",
"checked": true
},
{
"name": "Windows",
"value": "Windows 10"
}
]
},
{
"name": "Software",
"checkedCount": 0,
"children": [{
"name": "Photoshop",
"value": "PS",
"checked": true
},
{
"name": "Dreamweaver",
"value": "DW"
},
{
"name": "Fireworks",
"value": "FW",
"checked": true
}
]
}
]
I would like to loop through the array, check if each object has a children array and it in turn has a checked property which is set to true, then I should update the checkedCount in the parent object. So, result should be like this:
[{
"name": "Operating System",
"checkedCount": 1,
"children": [{
"name": "Linux",
"value": "Redhat",
"checked": true
},
{
"name": "Windows",
"value": "Windows 10"
}
]
},
{
"name": "Software",
"checkedCount": 2,
"children": [{
"name": "Photoshop",
"value": "PS",
"checked": true
},
{
"name": "Dreamweaver",
"value": "DW"
},
{
"name": "Fireworks",
"value": "FW",
"checked": true
}
]
}
]
I tried to do it this way in angular, but this is in-efficient and results in an error saying this.allFilters[i].children[j] may be undefined. So, looking for an efficient manner to do this.
for(let j=0;i<this.allFilters[i].children.length; j++) {
if (Object.keys(this.allFilters[i].children[j]).length > 0) {
if (Object.prototype.hasOwnProperty.call(this.allFilters[i].children[j], 'checked')) {
if(this.allFilters[i].children[j].checked) {
this.allFilters[i].checkedCount++;
}
}
}
}

Use a nested for loop to check all the children. If checked is truthy, increment the count of the parent. You don't need to check if parent.children has any elements since if there are no elements the loop won't run anyways.
// minified data
const data = [{"name":"Operating System","checkedCount":0,"children":[{"name":"Linux","value":"Redhat","checked":!0},{"name":"Windows","value":"Windows 10"}]},{"name":"Software","checkedCount":0,"children":[{"name":"Photoshop","value":"PS","checked":!0},{"name":"Dreamweaver","value":"DW"},{"name":"Fireworks","value":"FW","checked":!0}]}];
for (const parent of data) {
for (const child of parent.children) {
if (child.checked) parent.checkedCount++;
}
}
console.log(data);

No need to complicate it like that, you just need to check checked property in children.
data.forEach((v) => {
v.children.forEach((child) => {
if (child.checked) {
v.checkedCount++;
}
});
});

Using filter + length on children array should do the job:
const data = [{"name":"Operating System","checkedCount":null,"children":[{"name":"Linux","value":"Redhat","checked":true},{"name":"Windows","value":"Windows 10"}]},{"name":"Software","checkedCount":null,"children":[{"name":"Photoshop","value":"PS","checked":true},{"name":"Dreamweaver","value":"DW"},{"name":"Fireworks","value":"FW","checked":true}]}];
data.forEach(itm => {
itm.checkedCount = itm.children?.filter(e => e.checked === true).length ?? 0;
});
console.log(input);

I would suggest going functional.
Using map
const children = arr.map(obj => obj.children);
const result = children.map((child, idx) => {
const checkedCount = child.filter(obj => obj.checked)?.length;
return {
...arr[idx],
checkedCount
};
});
console.log(result)
or using forEach
const result = [];
const children = arr.map(obj => obj.children);
children.forEach((child, idx) => {
const checkedCount = child.filter(obj => obj.checked)?.length;
result[idx] = {
...arr[idx],
checkedCount
};
});
console.log(result)

nested filter array javascript

I want to create a nested filter in js
when I filter my array primary data is affected and changed but I need preliminary data to remove filters
my js code :
let result = companies;
result.map((item, i) => {212
let rows = [...result[i].table.table_rows].filter((item3) => {
return Object.keys(item3).some(i => item3[i][key] === value[key]);
});
result[i].table.table_rows = [...rows];
return result[i];
});
arrayFilter(result);
my data is:
{
"companies": [
{
"company": {
"name": "company 1"
},
"table": {
"table_rows": [
{
"cells": {
"product_name": "prod1",
"pa_size": "12"
}
},
{
"cells": {
"product_name": "prod2",
"pa_size": "15"
}
}
]
}
},
{
"company": {
"name": "company 2"
},
"table": {
"table_rows": [
{
"cells": {
"product_name": "prod2-1",
"pa_size": "12"
}
},
{
"cells": {
"product_name": "prod2-2",
"pa_size": "18"
}
}
]
}
}
]
}
I tried many ways to solve this problem, but I did not get the right answer

Your question is not clear, the point I have understand that you wanted to filter the array "table_rows" located inside each companies array object? map and filter returns new array, so the solution for this is:
result = result.companies.map((item, i) => {
const newItem = {...item};
let rows = newItem .table.table_rows.filter((item3) => {
return Object.keys(item3).some(i => item3[i][key] === value[key]);
});
newItem.table_rows = [...rows];
return newItem ;
});
arrayFilter(result);

how to get max value from a nested json array

I have a nested json array and I am trying to get the maximum value of the points attribute in this array.
data = {
"name": "KSE100",
"children": [
{
"name": "TECHNOLOGY & COMMUNICATION",
"children": [
{
"name": "TRG",
'points': -21
},
{
"name": "SYS",
},
]
},
{
"name": "OIL",
"children": [
{
"name": "PPL",
'points': 9
},
{
"name": "PSO",
'points': -19
},
]
},
]
}
I want the max value of points from under the children sections. I mean from under technology and oil sectors.
What I've done so far:
var max;
for (var i in data.children.length) {
for (var j in data.data[i]) {
var point = data.data[i].children[j]
}
}

Try the following:
data = {
"name": "KSE100",
"children": [
{
"name": "TECHNOLOGY & COMMUNICATION",
"children": [
{
"name": "TRG",
'points': -21
},
{
"name": "SYS",
},
]
},
{
"name": "OIL",
"children": [
{
"name": "PPL",
'points': 9
},
{
"name": "PSO",
'points': -19
},
]
},
]
}
var array = [];
for (var first of data.children) {
for (var second of first.children) {
if(second.points != undefined)
{
array.push(second);
}
}
}
var maximumValue = Math.max.apply(Math, array.map(function(obj) { return obj.points; }));
console.log(maximumValue);

you can use the reduce method on the array object to do this
const maxValues = []
data.children.forEach(el => {
if (el.name === 'OIL' || el.name === 'TECHNOLOGY & COMMUNICATIO'){
const max = el.children.reduce((current, previous) => {
if (current.points > previous.points) {
return current
}
}, 0)
maxValues.append({name: el.name, value: max.points})
}
})
This will give you an array of the objects with the name and max value.

First you can convert your object to a string through JSON.stringify so that you're able to use a regular expression
(?<=\"points\":)-?\\d*
To matchAll the values preceded by the pattern \"points\": that are or not negative values. After it, convert the result to a array through the spread operator ... and then reduce it to get the max value.
const data = {name:"KSE100",children:[{name:"TECHNOLOGY & COMMUNICATION",children:[{name:"TRG",points:-21},{name:"SYS"}]},{name:"OIL",children:[{name:"PPL",points:9},{name:"PSO",points:-19}]}]};
console.log(
[ ...JSON.stringify(data).matchAll('(?<=\"points\":)-?\\d*')]
.reduce((acc, curr) => Math.max(curr, acc))
)

I wasn't 100% sure, what your exact goal is, so I included a grouped max value and and overall max value with a slight functional approach.
Please be aware that some functionalities are not working in older browsers i.e. flatMap. This should anyways help you get started and move on.
const data = {
name: "KSE100",
children: [
{
name: "TECHNOLOGY & COMMUNICATION",
children: [
{
name: "TRG",
points: -21,
},
{
name: "SYS",
},
],
},
{
name: "OIL",
children: [
{
name: "PPL",
points: 9,
},
{
name: "PSO",
points: -19,
},
],
},
],
};
const maxPointsByGroup = data.children.reduce(
(acc, entry) => [
...acc,
{
name: entry.name,
max: Math.max(
...entry.children
.map((entry) => entry.points)
.filter((entry) => typeof entry === "number")
),
},
],
[]
);
console.log("grouped max:", maxPointsByGroup);
const overallMax = Math.max(
...data.children
.flatMap((entry) => entry.children.flatMap((entry) => entry.points))
.filter((entry) => typeof entry === "number")
);
console.log("overall max:", overallMax);

How to make payload response return data into different format?

I need to change the structure of the payload response from the REST call on the frontend. Right now the api returns the data in the following format:
[
{
"row": [
{
"name": "Desc",
"value": "7777 - Florida Hurricane"
},
{
"name": "DSTR_NR",
"value": "7777"
}
]
},
{
"row": [
{
"name": "Desc",
"value": "7172 - Virginia Severe Storm(s)"
},
{
"name": "DSTR_NR",
"value": "7172"
}
]
}
]
This is what I have so far but it does not give me the data in the proper format:
let result = payload.reduce(function(res, obj) {
let temp = obj.row.map(function(o) {
return Object.assign({}, o);
});
return res.concat(temp);
},[])
return result;
// instead, this returns the data in the following way:
{name: "Desc", value: "7777 - Florida Hurricane"}
{name: "DSTR_NR", value: "7777"}
How can I make the payload response structure into the following desired format?
{name: "7777 - Florida Hurricane", value: "7777"}
{name: "7172 - Virginia Severe Storm(s)", value: "7172"}
for name, I only want the value for Desc and
for value, I only want the value for DSTR_NR

I think that's what you're looking for:
const getDesiredFormat = response => response.map(data => {
const row = data['row']
return {
name: row[0].value,
value: row[1].value
}
}, [])

This should be easy.
Here you go..
var data = [
{
"row": [
{
"name": "Desc",
"value": "7777 - Florida Hurricane"
},
{
"name": "DSTR_NR",
"value": "7777"
}
]
},
{
"row": [
{
"name": "Desc",
"value": "7172 - Virginia Severe Storm(s)"
},
{
"name": "DSTR_NR",
"value": "7172"
}
]
}
].reduce((arr, value)=>{
var row = value.row;
arr.push({name:row.find(x=> x.name =="Desc").value, value:row.find(x=> x.name =="DSTR_NR").value})
return arr
},[])
console.log(data)

you can use map
var data = [{
"row": [{
"name": "Desc",
"value": "7777 - Florida Hurricane"
},
{
"name": "DSTR_NR",
"value": "7777"
}
]
},
{
"row": [{
"name": "Desc",
"value": "7172 - Virginia Severe Storm(s)"
},
{
"name": "DSTR_NR",
"value": "7172"
}
]
}
];
console.log(data.map(i => {
if (i.row.length) {
var val1 = i.row.find(f => f.name.toLowerCase() === "desc");
var val2 = i.row.find(f => f.name.toLowerCase() === "dstr_nr");
if (val1 && val2) {
return {
name: val1.value,
value: val2.value
};
}
}
}))

This should handle your problem
result = data.reduce(function(res, obj) {
let temp = obj.row.reduce(function(tempObj, element) {
if(element.name === "Desc"){tempObj.name = element.value}
else tempObj.value = element.value
return tempObj
}, {});
return res.concat(temp);
},[])

Group and count values in an array

I have an array with objects, like the following.
b = {
"issues": [{
"fields": {
"status": {
"id": "200",
"name": "Backlog"
}
}
}, {
"fields": {
"status": {
"id": "202",
"name": "close"
}
}
}, {
"fields": {
"status": {
"id": "201",
"name": "close"
}
}
}]
};
I want to count how many issues have status close, and how many have backlog. I'd like to save the count in a new array as follows.
a = [
{Name: 'Backlog', count: 1},
{Name: 'close', count: 2}
];
I have tried the following.
b.issues.forEach(function(i) {
var statusName = i.fields.status.name;
if (statusName in a.Name) {
a.count = +1;
} else {
a.push({
Name: statusName,
count: 1
});
}
});
That however doesn't seem to be working. How should I implement this?

This is a perfect opportunity to use Array#reduce. That function will take a function that is applied to all elements of the array in order and can be used to accumulate a value. We can use it to accumulate an object with the various counts in it.
To make things easy, we track the counts in an object as simply {name: count, otherName: otherCount}. For every element, we check if we already have an entry for name. If not, create one with count 0. Otherwise, increment the count. After the reduce, we can map the array of keys, stored as keys of the object, to be in the format described in the question. See below.
var b = {
"issues": [{
"fields": {
"status": {
"id": "200",
"name": "Backlog"
}
}
}, {
"fields": {
"status": {
"id": "202",
"name": "close"
}
}
}, {
"fields": {
"status": {
"id": "201",
"name": "close"
}
}
}]
};
var counts = b.issues.reduce((p, c) => {
var name = c.fields.status.name;
if (!p.hasOwnProperty(name)) {
p[name] = 0;
}
p[name]++;
return p;
}, {});
console.log(counts);
var countsExtended = Object.keys(counts).map(k => {
return {name: k, count: counts[k]}; });
console.log(countsExtended);
.as-console-wrapper {
max-height: 100% !important;
}
Notes.
Array#reduce does not modify the original array.
You can easily modify the function passed to reduce to for example not distinguish between Backlog and backlog by changing
var name = c.fields.status.name;
into
var name = c.fields.status.name.toLowerCase();
for example. More advanced functionality can also easily be implemented.

Using ES6 Arrow functions you can do it with minimum syntax
var b = {
"issues": [{
"fields": {
"status": {
"id": "200",
"name": "Backlog"
}
}
}, {
"fields": {
"status": {
"id": "202",
"name": "close"
}
}
}, {
"fields": {
"status": {
"id": "201",
"name": "close"
}
}
}]
};
var countOfBackLog = b.issues.filter(x => {
return x.fields.status.name === "Backlog"
}).length
var countOfClose = b.issues.filter(x => {
return x.fields.status.name === "close"
}).length
a =[{Name: 'Backlog', count : countOfBackLog}, {Name: 'close', count : countOfClose}]
More about arrow functions here

You can write like this. It is dynamic.
var a = {};
for(var key in b["issues"]){
if(!a.hasOwnProperty(b["issues"][key].fields.status.name)){
a[b["issues"][key].fields.status.name] = 1;
}else{
a[b["issues"][key].fields.status.name] = a[b["issues"][key].fields.status.name]+1;
}
}
var c = [];
for(var key1 in a){
c.push({
name : key1,
count : a[key1]
});
}

Something like this should do the trick. Simply iterate over your data, keep 2 counters with the number of each type of issue, and create the data format you want in the end. Try it live on jsfiddle.
var b = {
"issues": [{
"fields": {
"status": {
"id": "200",
"name": "Backlog"
}
}
}, {
"fields": {
"status": {
"id": "202",
"name": "close"
}
}
}, {
"fields": {
"status": {
"id": "201",
"name": "close"
}
}
}]
};
var data = [];
for(var issue of b.issues){
var entryFound = false;
var tempObj = {
name: issue.fields.status.name,
count: 1
};
for(var item of data){
if(item.name === tempObj.name){
item.count++;
entryFound = true;
break;
}
}
if(!entryFound){
data.push(tempObj);
}
}
console.log(data);