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Array of objects how do i check for deeply nested text string duplicates & remove from array?

I have an array of objects
Deep inside those objects is a text string
I want to check if other objects in the same array have the same text string / are duplicates.
Then i need a new array with those duplicates removed.
I thought this would be quite simple but it's been testing my intellect for two days now.
const arr = [
{..obj 1}
{..obj 2}
{..obj 3}
{
id: 4,
uid: 24872-2847-249249892842,
tags: ['some', 'stuff'],
type: "blogpage",
href: "https://link-to-stuff",
first_publication_date: "2020-02-12T16:05:04+0000",
last_publication_date: "2020-02-18T21:52:06+0000",
data: {
...some stuff
heading: [
{ type: "heading1", text: "Here Is My Text I Need To Check Duplicates
Of"}
]
}
}
{..obj 5}
{..obj 6}
{..obj 7}
{..obj 8}
{..obj 9}
{..obj 10}
]
I figured something like:
filterOutDuplicates = (blogIndexContent) => {
let arr = blogIndexContent.pages;
let results = [];
arr.map(each => {
if (!results || !results.length) {
results.push(each);
} else {
for (let i = 0; i < results.length; i++) {
const headline = results[i].data.heading[0].text;
if (headline === each.data.heading[0].text) {
return;
} else {
return results.push(each);
}
}
}
})
console.log('Results :', results); // <-- this just gives me the same 9 blog stories again, no duplicates removed.
}
What am i doing wrong guys?

If you dont mind using lodash, it could be easily solved using _.uniqBy
const withoutDups = _.uniqBy(arr, 'data.heading[0].text')

Try this
const arr = [
{
id: 4,
data: {
heading: [
{
type: "heading1",
text: "Here Is My Text I Need To Check Duplicates Of"
}
]
}
},
{
id: 5,
data: {
heading: [
{
type: "heading1",
text: "Here Is My Text I Need To Check Duplicates Of"
}
]
}
},
{
id: 6,
data: {
heading: [
{
type: "heading1",
text: "Not Duplicates"
}
]
}
}
];
const withoutDuplicates = arr.reduce(
(prev, curr) =>
prev
.map(d => d["data"]["heading"][0]["text"])
.includes(curr["data"]["heading"][0]["text"])
? [curr]
: [...prev, curr],
[]
);
console.log(withoutDuplicates);

Slight changes to your code
1) remove using map, have loop over array.
2) Build the uniq object with keys. (Here headline is what we want)
3) Add to results array only when key is not in uniq
let arr = blogIndexContent.pages;
let results = [];
const uniq = {};
for (let i = 0; i < arr.length; i++) {
const headline = arr[i].data.heading[0].text;
if (!(headline in uniq)) {
results.push(each);
uniq[each] = 1;
}
}
console.log("Results :", results);

This should work for you:
filterOutDuplicates = blogIndexContent => {
let arr = blogIndexContent.pages
const result = []
arr.forEach(each => {
if (result.length === 0) {
result.push(each)
}
else {
const headline = each.data.heading[0].text
let found = false
for (let i = 0; i < result.length; i++) {
if (result[i].data.heading[0].text === headline) {
found = true
break
}
}
if (!found) {
result.push(each)
}
}
})
console.log('Results :', results)
}

how to use nested arrays to form objects in javascript using the first array as object and the rest of the array as value

I was given an array such as this :
data = [
['first_name', 'second_name', 'sex'],
['Jacob', 'David', 'M'],
['Kathryn', 'Gardener', 'F'],
['Jamaal', 'Dave', 'Unknown']
].
the solution is to return the array as an object looking something like this :
[
{ first_name: "Jacob", second_name: "David", sex: "M" },
{ first_name: "Kathryn", second_name: "Gardener", sex: "F" }
{....}
];
I wrote the following code :
var object = {};
var arrays = [];
for (i = 0; i < data.length; i++){
for (var j = i; j < data.length; j++){
var keys = data[0][i];
var values = data [j][i];
object[keys] = values;
}
arrays.push(object);
};
but the output I'm having is :
[
{
first_name :'Jamaal',
second_name : 'Dave',
sex : 'unknown'
},
{
first_name :'Jamaal',
second_name : 'Dave',
sex : 'unknown'
},
{
first_name :'Jamaal',
second_name : 'Dave',
sex : 'unknown'
},
{
first_name :'Jamaal',
second_name : 'Dave',
sex : 'unknown'
}
];
I've also tried several ways either i end up with being able to create only one object...

You need new object (references) inside of the first loop, otherwise you get the same object for every row.
var data = [ ['first_name', 'second_name', 'sex'], ['Jacob', 'David', 'M'], ['Kathryn', 'Gardener', 'F'], ['Jamaal', 'Dave', 'Unknown']],
result = [],
i, j,
object;
for (i = 0; i < data.length; i++) {
object = {}; // take a new object
for (j = 0; j < data[i].length; j++) { // start from zero
object[data[0][j]] = data[i][j]; // use j as last key
}
result.push(object);
}
console.log(result);
.as-console-wrapper { max-height: 100% !important; top: 0; }
A shorter approach with Object.fromEntries.
const
getObjects = ([header, ...data]) => data.map(values =>
Object.fromEntries(values.map((value, index) => [header[index], value])));
var data = [['first_name', 'second_name', 'sex'], ['Jacob', 'David', 'M'], ['Kathryn', 'Gardener', 'F'], ['Jamaal', 'Dave', 'Unknown']],
result = getObjects(data);
console.log(result);
.as-console-wrapper { max-height: 100% !important; top: 0; }

you can do something like this
dataToObj=(data)=>{
let head=data[0];
let result=[];
for(let i=1;i<data.length;i++){
let obj={};
for(let j=0;j<head.length;j++){
obj[head[j]]=data[i][j]
}
result.push(obj);
}
return result;
}

var data = [
['first_name', 'second_name', 'sex'],
['Jacob', 'David', 'M'],
['Kathryn', 'Gardener', 'F'],
['Jamaal', 'Dave', 'Unknown']
]
function createObject(arr){
var arr2 = [];
keysArr = arr[0];
arr.splice(0,1);
arr.forEach(function(x,i){
arr2[i] = {};
arr[i].forEach(function(y,j){
arr2[i][keysArr[j]] = arr[i][j];
});
});
return arr2;
}
createObject(data);

Since no one have posted a example with map i might as well do that, it's short and sweet!
var data = [['first_name', 'second_name', 'sex'],['Jacob', 'David', 'M'],['Kathryn', 'Gardener', 'F'],['Jamaal', 'Dave', 'Unknown']]
var res = []
data.slice(1).map((x, i) => {
var obj = {}
x.map((c, j) => {
obj[data[0][j]] = x[j]
})
res.push(obj)
})
console.log(res)

How to convert an unorganized array into an grouped array by id

I'm trying to create an array that contains objects with an id and amount, grouped by id. The ids needs to be unique. So if there is 2 objects with same id, the amount will be added.
I can do it with nested for-loops, but I find this solution inelegant and huge. Is there a more efficient or cleaner way of doing it?
var bigArray = [];
// big Array has is the source, it has all the objects
// let's give it 4 sample objects
var object1 = {
id: 1,
amount: 50
}
var object2 = {
id: 2,
amount: 50
}
var object3 = {
id: 1,
amount: 150
}
var object4 = {
id: 2,
amount:100
}
bigArray.push(object1,object2,object3,object4);
// organizedArray is the array that has unique ids with added sum. this is what I'm trying to get
var organizedArray = [];
organizedArray.push(object1);
for(var i = 1; i < bigArray.length; i++ ) {
// a boolean to keep track whether the object was added
var added = false;
for (var j = 0; j < organizedArray.length; j++){
if (organizedArray[j].id === bigArray[i].id) {
organizedArray[j].amount += bigArray[i].amount;
added = true;
}
}
if (!added){
// it has object with new id, push it to the array
organizedArray.push(bigArray[i]);
}
}
console.log(organizedArray);

You can definitly make it cleaner and shorter by using reduce, not sure about efficiency though, i would say a traditional for loop is more efficient :
var bigArray = [];
var object1 = {id: 1, amount: 50}
var object2 = {id: 2, amount: 50}
var object3 = {id: 1, amount: 150}
var object4 = {id: 2, amount: 100}
bigArray.push(object1, object2, object3, object4);
var organizedArray = bigArray.reduce((acc, curr) => {
// check if the object is in the accumulator
const ndx = acc.findIndex(e => e.id === curr.id);
if(ndx > -1) // add the amount if it exists
acc[ndx].amount += curr.amount;
else // push the object to the array if doesn't
acc.push(curr);
return acc;
}, []);
console.log(organizedArray)

Rather than an organized array, how about a single object whose keys are the ids and values are the sums.
var bigArray = [
{ id: 1, amount: 50 },
{ id: 2, amount: 50 },
{ id: 1, amount: 150 },
{ id: 2, amount: 100 }
];
let total = {}
bigArray.forEach(obj => {
total[obj.id] = (total[obj.id] || 0) + obj.amount;
});
console.log(total);
If you really need to convert this to an array of objects then you can map the keys to objects of your choosing like this:
var bigArray = [
{ id: 1, amount: 50 },
{ id: 2, amount: 50 },
{ id: 1, amount: 150 },
{ id: 2, amount: 100 }
];
let total = {}
bigArray.forEach(obj => {
total[obj.id] = (total[obj.id] || 0) + obj.amount;
});
console.log(total);
// If you need the organized array:
let organizedArray = Object.keys(total).map(key => ({ id: key, amount: total[key] }));
console.log(organizedArray);

function getUniqueSums(array) {
const uniqueElements = [];
const arrayLength = array.length;
for(let index = 0; index < arrayLength; index++) {
const element = array[index];
const id = element.id;
const uniqueElement = findElementByPropertyValue(uniqueElements, 'id', id);
if (uniqueElement !== null) {
uniqueElement.amount += element.amount;
continue;
}
uniqueElements.push(element);
}
return uniqueElements;
}
function findElementByPropertyValue(array, property, expectedValue) {
const arrayLength = array.length;
for(let index = 0; index < arrayLength; index++) {
const element = array[index];
const value = element[property];
if (value !== expectedValue) {
continue;
}
return element;
}
return null;
}
This is an untested code. You will be able to understand the logic. Logic is almost same yours. But, perhaps a more readable code.

how to count duplicate values object to be a value of object

how to count the value of object in new object values
lets say that i have json like this :
let data = [{
no: 3,
name: 'drink'
},
{
no: 90,
name: 'eat'
},
{
no: 20,
name: 'swim'
}
];
if i have the user pick no in arrays : [3,3,3,3,3,3,3,3,3,3,3,90,20,20,20,20]
so the output should be an array
[
{
num: 3,
total: 11
},
{
num: 90,
total: 1
},
{
num:20,
total: 4
}
];
I would like to know how to do this with a for/of loop
Here is the code I've attempted:
let obj = [];
for (i of arr){
for (j of data){
let innerObj={};
innerObj.num = i
obj.push(innerObj)
}
}

const data = [{"no":3,"name":"drink"},{"no":90,"name":"eat"},{"no":20,"name":"swim"}];
const arr = [3,3,3,3,3,3,3,3,3,3,3,20,20,20,20,80,80];
const lookup = {};
// Loop over the duplicate array and create an
// object that contains the totals
for (let el of arr) {
// If the key doesn't exist set it to zero,
// otherwise add 1 to it
lookup[el] = (lookup[el] || 0) + 1;
}
const out = [];
// Then loop over the data updating the objects
// with the totals found in the lookup object
for (let obj of data) {
lookup[obj.no] && out.push({
no: obj.no,
total: lookup[obj.no]
});
}
document.querySelector('#lookup').textContent = JSON.stringify(lookup, null, 2);
document.querySelector('#out').textContent = JSON.stringify(out, null, 2);
<h3>Lookup output</h3>
<pre id="lookup"></pre>
<h3>Main output</h3>
<pre id="out"></pre>

Perhaps something like this? You can map the existing data array and attach filtered array counts to each array object.
let data = [
{
no: 3,
name: 'drink'
},
{
no:90,
name: 'eat'
},
{
no:20,
name: 'swim'
}
]
const test = [3,3,3,3,3,3,3,3,3,3,3,90,20,20,20,20]
const result = data.map((item) => {
return {
num: item.no,
total: test.filter(i => i === item.no).length // filters number array and then checks length
}
})

You can check next approach using a single for/of loop. But first I have to create a Set with valid ids, so I can discard noise data from the test array:
const data = [
{no: 3, name: 'drink'},
{no: 90, name: 'eat'},
{no: 20, name: 'swim'}
];
const userArr = [3,3,3,3,3,3,3,3,7,7,9,9,3,3,3,90,20,20,20,20];
let ids = new Set(data.map(x => x.no));
let newArr = [];
for (i of userArr)
{
let found = newArr.findIndex(x => x.num === i)
if (found >= 0)
newArr[found].total += 1;
else
ids.has(i) && newArr.push({num: i, total: 1});
}
console.log(newArr);

Fill in missing properties in an array of objects

What is the best way to fill in missing properties in an array of objects, such as this example:
[
{
name: 'Tom',
number: '01234 567 890',
website: 'http://www.tom.com'
},
{
name: 'Richard',
number '07777 666 555'
},
{
name: 'Harry',
website: 'http://www.harry.com'
}
]
I need to add the missing properties with a null value, so that when I pass this array on to be rendered in something such as a HTML table or CSV file, everything lines up correctly. I was thinking of passing over the array twice, once to get all the possible properties, and a second time to add those missing properties with a null value to each object where it doesn't exist. Is there a better way to do this?
EDIT: I won't know what the keys are until I have the data, it's coming from an API and the keys are not always requested explicitly.
My final solution
Thanks all, it seems the two pass approach is indeed the best approach. After I started to write this using the examples provided, I realised that the order of the properties wasn't being maintained. This is how I achieved filling in the missing props, and maintaining the correct order. Any suggestions for potential improvements are welcome.
var fillMissingProps = function(arr) {
// build a list of keys in the correct order
var keys = [];
arr.forEach(function(obj) {
var lastIndex = -1;
Object.keys(obj).forEach(function(key, i) {
if (keys.includes(key)) {
// record the position of the existing key
lastIndex = keys.lastIndexOf(key);
if (lastIndex < i) {
// this key is in the wrong position so move it
keys.splice(i, 0, keys.splice(lastIndex, 1)[0]);
lastIndex = i;
}
} else {
// add the new key in the correct position
// after the previous existing key
lastIndex++;
keys.splice(lastIndex, 0, key);
}
});
});
// build a template object with all props set to null
// and in the correct position
var defaults = {};
keys.forEach(function(key) {
defaults[key] = null;
});
// and update the array by overwriting each element with a
// new object that's built from the template and the original object
arr.forEach(function(obj, i, arr) {
arr[i] = Object.assign({}, defaults, obj);
});
return arr;
};
/** TEST **/
var currentArray = [
{
website: 'http://www.unknown.com'
},
{
name: 'Tom',
number: '01234 567 890',
website: 'http://www.tom.com'
},
{
title: 'Mr',
name: 'Richard',
gender: 'Male',
number: '04321 666 555'
},
{
id: '003ABCDEFGHIJKL',
name: 'Harry',
website: 'http://www.harry.com',
mobile: '07890 123 456',
city: 'Brentwood',
county: 'Essex'
}
];
var newArray = fillMissingProps(currentArray);
for (var i = 0; i < newArray.length; i++) {
for (var prop in newArray[i]) {
console.log(prop + ": " + newArray[i][prop]);
}
console.log('---------');
}

Given that you don't know apriori which keys are supposed to exist, you have no choice but to iterate over the array twice:
// build a map of unique keys (with null values)
var keys = {}
array.forEach(el => Object.keys(el).forEach(k => keys[k] = null));
// and update the array by overwriting each element with a
// new object that's built from the null map and the original object
array.forEach((el, ix, a) => a[ix] = Object.assign({}, keys, el));

Use Array.prototype.map():
const arr = [
{
name: 'Tom',
number: '01234 567 890',
website: 'http://www.tom.com',
},
{
name: 'Richard',
number: '07777 666 555',
},
{
name: 'Harry',
website: 'http://www.harry.com',
},
];
const newArr = arr.map(x => (
arr.map(x => Object.keys(x))
.reduce((a, b) =>
(b.forEach(z => a.includes(z) || a.push(z)), a)
)
.forEach(
y => (x[y] = x.hasOwnProperty(y) ? x[y] : null)
), x)
);
console.log(newArr);

Here is a more interesting answer, its a tad fun one but it will build up your objects on the fly as new properties appear:
var currentArray = [
{
name: 'Tom',
number: '01234 567 890',
website: 'http://www.tom.com'
},
{
name: 'Richard',
number: '07777 666 555'
},
{
name: 'Harry',
website: 'http://www.harry.com'
}
]
var newArray = []
function NewObject() {
}
for(var i = 0; i < currentArray.length; i++){
var nObj = new NewObject();
for(var prop in currentArray[i]){
if(!NewObject.hasOwnProperty(prop))
NewObject.prototype[prop] = null;
nObj[prop]=currentArray[i][prop];
}
newArray.push(nObj);
}
for(var i = 0; i < newArray.length; i++){
for(var prop in newArray[i]){
console.log(prop+ ": "+newArray[i][prop]);
}
console.log('---------');
}
It builds new objects from the ones you provide and adds new properties to the objects if they don't exist already.
This idea was more for curiosities sake tho so any comments would be interesting :)

You can get all keys and set all keys using for..of loop, .map() to iterate all Object.keys(), redefine original array
var arr = [{
name: 'Harry',
website: 'http://www.harry.com'
},{
name: 'Tom',
number: '01234 567 890',
website: 'http://www.tom.com'
}, {
name: 'Richard',
number: '07777 666 555'
}];
for (var obj of arr) {
for (var key of Object.keys(obj)) {
arr = arr.map(o => (o[key] = o[key] || null, o))
}
};
console.log(arr);

Something like this could work:
for (var i = 0; i < arrayLength; i++) {
yourArray[i].name = yourArray[i].name || null;
yourArray[i].number = yourArray[i].number || null;
yourArray[i].website= yourArray[i].website|| null;
}