Develop Reference

How would I filter an array of objects by : If id numbers are consecutive

I have a JSON file that has an array of objects with data inside :
[
{
"_id": "62bd5fba34a8f1c90303055c",
"index": 0,
"email": "mcdonaldholden#xerex.com",
"nameList": [
{
"id": 0,
"name": "Wendi Mooney"
},
{
"id": 2,
"name": "Holloway Whitehead"
}
]
},
{
"_id": "62bd5fbac3e5a4fca5e85e81",
"index": 1,
"nameList": [
{
"id": 0,
"name": "Janine Barrett"
},
{
"id": 1,
"name": "Odonnell Savage"
},
{
"id": 2,
"name": "Patty Owen"
}
]
}, ...
My job is to filter the arrays that have more than two names and if their id are consecutive.
I managed to sort users with more than two user.name but cant grasp the concept of filtering consecutive id numbers
let lister3 = userData.filter(names => names?.nameList?.filter(name => name?.name).length > 2)
Which returns me the objects with more than two user names.

filter takes a function that returns true if you want to retain the item or false if not. In this function, you could check the length of the nameList, and then iterate over its members and make sure their ids are consecutive:
retult = userData.filter(u => {
if (u.nameList.length < 2) {
return false;
}
for (let i = 1; i < u.nameList.length; ++i) {
if (u.nameList[i].id != u.nameList[i - 1].id + 1) {
return false;
}
}
return true;
});

a item should need tow conditions,one is nameList length is two ,the other is the itemId of nameList is consecutive;
so first as you do :
`
let lister3 = userData.filter(names => names?.nameList?.filter(name => name?.name).length > 2)
`
;
then
`
let lister4 = lister3.filter(names=>{
let idOfStr = names.nameList?.sort((a,b)=>a.id-b.id).map(item=>item.id).join("");
let resultStr = Array.from(idOfStr.length).fill(+idOfStr[0]).map((item,index)=>+item+index).join('');
return idOfStr === resultStr
})
`
hope this is useful for you

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 create a JS object and append it to an array

I have the following data :
const data=
{
"1": [
{
"sales_project_id": 5,
"sales_project_name": "name",
"sales_project_est_rev": "123.00",
"project_status": {
"id": 1,
"label": "Start",
"description": null
}
},
{
"sales_project_id": 6,
"sales_project_name": "name2",
"sales_project_est_rev": "123.00",
"project_status": {
"id": 1,
"label": "Start",
"description": null
}
}
],
"2": [],
"4": []
}
These data are grouped in my backend based on their Status , in this case im only showing 2 status , but they are dynamic and can be anything the user defines.
What i wish to do is to transform the above data into the format below :
const data =
{
columns: [
{
id: // id of status here,
title: //label of status here,
cards: [
{
id : //sales_project_id here,
title: //sales_project_name here,
},
]
},
{
id: // id of status here,
title: //label of status here,
cards: [
{
id : //sales_project_id here,
title: //sales_project_name here,
},
]
}
]}
My guess would be to iterate over the data , however i am pretty unfamiliar with doing so , would appreciate someone's help!
Here is what i could come up with so far:
const array = []
Object.keys(a).map(function(keyName, keyIndex) {
a[keyName].forEach(element => {
#creating an object of the columns array here
});
})

after some trial and error , manage to accomplish this , however , im not sure if this is a good method to do so.
Object.keys(projects).map(function(keyName, keyIndex) {
// use keyName to get current key's name
// and a[keyName] to get its value
var project_object = {}
project_object['id'] = projects[keyName][0].id
project_object['title'] = projects[keyName][0].label
project_object['description'] = projects[keyName][0].description
console.log( projects[keyName][1])
var card_array = []
projects[keyName][1].forEach(element => {
var card = {}
card["id"] = element.sales_project_id
card["title"] = element.sales_project_name
card["description"] = element.sales_project_est_rev
card_array.push(card)
});
project_object["cards"] = card_array
array.push(project_object)
})
Im basically manipulating some the scope of the variables inorder to achieve this

See my solution, I use Object.keys like you, then I use reduce:
const newData = { columns: Object.keys(data).map((item) => {
return data[item].reduce((acc,rec) => {
if (typeof acc.id === 'undefined'){
acc = { id: rec.project_status.id, title: rec.project_status.label, ...acc }
}
return {...acc, cards: [...acc.cards, { id:rec.sales_project_id, title:rec.sales_project_name}]}
}, {cards:[]})
})}
See full example in playground: https://jscomplete.com/playground/s510194

I'd just do this. Get the values of data using Object.values(data) and then use reduce to accumulate the desired result
const data=
{
"1": [
{
"sales_project_id": 5,
"sales_project_name": "name",
"sales_project_est_rev": "123.00",
"project_status": {
"id": 1,
"label": "Start",
"description": null
}
},
{
"sales_project_id": 6,
"sales_project_name": "name2",
"sales_project_est_rev": "123.00",
"project_status": {
"id": 1,
"label": "Start",
"description": null
}
}
],
"2": [],
"4": []
};
const a = Object.values(data)
let res =a.reduce((acc, elem)=>{
elem.forEach((x)=>{
var obj = {
id : x.project_status.id,
title : x.project_status.label,
cards : [{
id: x.sales_project_id,
title: x.sales_project_name
}]
}
acc.columns.push(obj);
})
return acc
},{columns: []});
console.log(res)

Sort by the sum of array in object

I am looking for a solution to sort an array by the sum of an array property within an object.
For example if the main array is
[
{
"Grid": {
"Day": [
11,
12
]
},
"Name": "One"
},
{
"Grid": {
"Day": [
5,
2
]
},
"Name": "Two"
}
]
How can I sort the sum of Day to return as
[
{
"Grid": {
"Day": [
5,
2
]
},
"Name": "Two"
},
{
"Grid": {
"Day": [
11,
12
]
},
"Name": "One"
}
]

You just need sort your array with comparator, that uses reduce to calc sum of inner array values:
let arr = [{"Grid": {"Day": [11,12]}, "Name": "One"},
{"Grid": {"Day": [5,2]}, "Name": "Two"},
{"Grid": {"Day": [1,2]}, "Name": "Two"}];
let sum = el => el.Grid.Day.reduce((a,b) => a + b);
arr.sort((a,b) => sum(a) - sum(b));
console.log(arr)

You can use a combination of reduce to sum the array, and sort to order the output:
var input = [
{
"Grid": {
"Day": [
11,
12
]
},
"Name": "One"
},
{
"Grid": {
"Day": [
5,
2
]
},
"Name": "Two"
}
];
var result = input.sort( (a,b) => sumOfDay(a) - sumOfDay(b));
console.log(result);
function sumOfDay(obj){
return obj.Grid.Day.reduce( (acc,curr) => acc + curr, 0);
}
Note that Array.prototype.sort actually mutates the original array in place. so the above could also do
input.sort( (a,b) => sumOfDay(a) - sumOfDay(b));
console.log(input);
So, don't fall into the trap of thinking the original array is unchanged just because I assigned the result to result!.
If you do wish to sort a copy of the array do this:
var result = input.slice().sort( (a,b) => sumOfDay(a) - sumOfDay(b));

Create a new Array of a by mapping through it and using reduce on the Day Array of Grid to get your sum which you can compare within a sort to return your list sorted by summed days.
const a = [
{
"Grid": {
"Day": [
11,
12
]
},
"Name": "One"
},
{
"Grid": {
"Day": [
5,
2
]
},
"Name": "Two"
}
]
const daySum = ({Grid}) => Grid.Day.reduce((prev, curr) => prev+curr, 0)
const sorted = [...a].sort(daySum)
console.log(sorted)
console.log(a) //Original array intact

Just "another" approach to solve the issue: assuming you (someday, later, eventually) may need to sort again, a good approach may also be to add a property to each grid item holding the sum of the days, avoiding the .reduce call every time you need to sort the array.
In this approach, .forEach is used to create the new property (through .reduce), and then .sort is used to sort the array in-place.
const input = [
{
"Grid": {
"Day": [
11,
12
]
},
"Name": "One"
},
{
"Grid": {
"Day": [
5,
2
]
},
"Name": "Two"
}
];
// Add a DaySum property evaluating the sum of the days.
input.forEach(i => i.Grid.DaySum = i.Grid.Day.reduce((a,b) => a + b));
// ^--- the second parameter (initial value) is unneeded here due to the fact that all elements are actually numeric, hence if the initial value is the first element of the array, which is a number already.
// Sor the array by that property.
input.sort((a,b) => a.Grid.DaySum - b.Grid.DaySum);
console.log(input);
Or, as suggested by #Andreas below, you can directly assign the property while sorting:
const input = [
{
"Grid": {
"Day": [
11,
12
]
},
"Name": "One"
},
{
"Grid": {
"Day": [
5,
2
]
},
"Name": "Two"
}
];
const sum = (a,b) => a + b;
input.sort((a,b) => {
a.Grid.DaySum = a.Grid.DaySum || a.Grid.Day.reduce(sum);
b.Grid.DaySum = b.Grid.DaySum || b.Grid.Day.reduce(sum);
return a.Grid.DaySum - b.Grid.DaySum;
});
console.log(input);

Sort-Index from nested JSON with Javascript

How can I recursively add a sort key to an infinite hierarchy like this:
[
{
"id": "D41F4D3D-EA9C-4A38-A504-4415086EFFF8",
"name": "A",
"parent_id": null,
"sortNr": 1,
"children": [
{
"id": "07E556EE-F66F-49B5-B5E4-54AFC6A4DD9F",
"name": "A-C",
"parent_id": "D41F4D3D-EA9C-4A38-A504-4415086EFFF8",
"sortNr": 3,
"children": []
},
{
"id": "8C63981E-0D30-4244-94BE-658BAAF40EF3",
"name": "A-A",
"parent_id": "D41F4D3D-EA9C-4A38-A504-4415086EFFF8",
"sortNr": 1,
"children": [
{
"id": "0BA32F23-A2CD-4488-8868-40AD5E0D3F09",
"name": "A-A-A",
"parent_id": "8C63981E-0D30-4244-94BE-658BAAF40EF3",
"sortNr": 1,
"children": []
}
]
},
{
"id": "17A07D6E-462F-4983-B308-7D0F6ADC5328",
"name": "A-B",
"parent_id": "D41F4D3D-EA9C-4A38-A504-4415086EFFF8",
"sortNr": 2,
"children": []
}
]
},
{
"id": "64535599-13F1-474C-98D0-67337562A621",
"name": "B",
"parent_id": null,
"sortNr": 2,
"children": []
},
{
"id": "1CE38295-B933-4457-BBAB-F1B4A4AFC828",
"name": "C",
"parent_id": null,
"sortNr": 3,
"children": [
{
"id": "D1E02274-33AA-476E-BA31-A4E60438C23F",
"name": "C-A",
"parent_id": "1CE38295-B933-4457-BBAB-F1B4A4AFC828",
"sortNr": 1,
"children": [
{
"id": "76A8259C-650D-482B-91CE-D69D379EB759",
"name": "C-A-A",
"parent_id": "D1E02274-33AA-476E-BA31-A4E60438C23F",
"sortNr": 1,
"children": []
}
]
}
]
}
]
I want to get a sortable index.
For example 0000.0001.0003 or 0001.0003 for node A-C.
The function for leadingZeroes is
function fillZeroes (num) {
var result = ('0000'+num).slice(-4);
if (num===null){
return result
} else {
return '0000';
}
}
It should be sorted by sort number in each level of hierarchy, the sort number should be set newly every time, because I want to do rearrangement by setting it 1,5 to insert it between 1 and 2 (later for drag and drop capability). so 1;1,5;2 should become 1;2;3 and can then be translated to a sort-index like above.
I will also need it for indentation and breadcrumb-stuff.
How do I insert the proper sort-index to each object ?
The question is mainly about the recursion part. I am quite new to JavaScript
Thanks a lot

Based on great answer by #georg. A bit adjusted solution based on sortNr object property.
You can run it straight as is with json being your object. The sort index is written into sortOrder property.
// Mutates the given object in-place.
// Assigns sortOrder property to each nested object
const indexJson = (json) => {
const obj = {children: json};
const format = (xs) => xs.map(x => pad(x, 4)).join('.');
const pad = (x, w) => (10 ** w + x).toString().slice(-w);
const renumber = (obj, path) => {
obj.path = path;
obj.sortOrder = format(path);
obj.children.slice()
.sort((obj1, obj2) => obj1.sortNr - obj2.sortNr)
.forEach((c, n) => renumber(c, path.concat(n+1)));
};
renumber(obj, []);
};
indexJson(json);
console.log(JSON.stringify(json, null, 2));

Basically
let renumber = (obj, path) => {
obj.path = path
obj.children.forEach((c, n) => renumber(c, path.concat(n)))
}
renumber({children: yourData}, [])
this creates a path property, which is an array of relative numbers. If you want to format it in a special way, then you can do
obj.path = format(path)
where format is like
let format = xs => xs.map(pad(4)).join(',')
let pad = w => x => (10 ** w + x).toString().slice(-w)