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Can this algorithm be made more efficient?

Currently I have an algorithm that runs to compare to different arrays of objects.
const allGroups = [{ id: '12345', name: 'groupOne'}, {id: '23421', name: 'groupTwo'},
{id: '28182', name: 'groupThree'}]
const clientsGroups = [{ id: 'abcde', clientGroupID: '12345'}, {id: 'dfcdae', clientGroupID: '93282'},
{id: 'jakdab', clientGroupID: '28182'}, {id: 'oiewad', clientGroupID: '93482'}]
const updateClientGroups = (allGroups, clientsGroups) => {
let allGroupsCopy = [...allGroups];
for (let i = 0; i < allGroupsCopy.length; i++) {
const allGroupsId = allGroupsCopy[i].id;
for (let j = 0; j < clientsGroups.length; j++) {
if (allGroupsId === clientsGroups[j].clientGroupID) {
allGroupsCopy[i] = {
...allGroupsCopy[i],
inGroup: true,
clientGroupID: clientsGroups[j].id,
};
}
}
}
return allGroupsCopy;
};
I check two different arrays of objects, if the id of allGroups matches the clientGroupID of clientGroups, I mutate the 'allGroupsCopy' to have 'inGroup: true' and add in the id of the clientsGroups.
The problem with this algorithm is it runs in n^2 time. Is there a more efficient way to do this?

Without changing the original arrays, could this be the an optimization ?
const allGroups = [
{ id: "12345", name: "groupOne" },
{ id: "23421", name: "groupTwo" },
{ id: "28182", name: "groupThree" },
];
const clientsGroups = [
{ id: "abcde", clientGroupID: "12345" },
{ id: "dfcdae", clientGroupID: "93282" },
{ id: "jakdab", clientGroupID: "28182" },
{ id: "oiewad", clientGroupID: "93482" },
];
const updateClientGroups = (groups, clients) => {
return clients.reduce((acum, current) => {
const isInGroup = groups.find((group) => group.id === current.clientGroupID);
acum.push({
...current,
inGroup: Boolean(isInGroup),
});
return acum;
}, []);
};
updateClientGroups(allGroups, clientsGroups)

If you change allGroups structure from array to map, you can do the job in linear time.
Something like:
const allGroups = {
'12345': { id: '12345', name: 'groupOne'}
...
}
const updateClientGroups = (allGroups, clientsGroups) => {
const clientGroupsMap = {};
clientsGroups.forEach(({clientGroupID}) =>
if(allGroups[clientGroupID]) {
clientGroupsMap[clientGroupID] = {...allGroups[clientGroupID], inGroup: true};
}
);
return {...allGroups, ...clientGroupsMap};
};

Return similar values ​from multiple array of objects in Javascript

Guys I made a simple example to illustrate my problem. I have 3 object arrays, datasOne, datasTwo and datasThree and what I want is to return a new array only with the objects that are in the 3 arrays. For example, if there is only Gustavo in the 3 arrays, then he will be returned. But there is a detail that if the datasThree is an empty array, then it will bring the data in common only from datasOne and datasTwo and if only the datasTwo which has data and the other two arrays have empty, then it will return data only from datasTwo. In other words it is to return similar data only from arrays that have data. I managed to do this algorithm and it works the way I want, but I would like to know another way to make it less verbose and maybe simpler and also work in case I add more arrays to compare like a dataFour for example. I appreciate anyone who can help me.
My code below:
let datasOne = [
{ id: 1, name: 'Gustavo' },
{ id: 2, name: 'Ana' },
{ id: 3, name: 'Luiz' },
{ id: 8, name: 'Alice' }
]
let datasTwo = [
{ id: 1, name: 'Gustavo' },
{ id: 3, name: 'Luiz' },
{ id: 8, name: 'Alice' }
]
let datasThree = [
{ id: 1, name: 'Gustavo' },
{ id: 3, name: 'Luiz' },
{ id: 2, name: 'Ana' },
{ id: 5, name: 'Kelly' },
{ id: 4, name: 'David' }
]
let filtered
if (datasOne.length > 0 && datasTwo.length > 0 && datasThree.length > 0) {
filtered = datasOne.filter(firstData => {
let f1 = datasThree.filter(
secondData => firstData.id === secondData.id
).length
let f2 = datasTwo.filter(
secondData => firstData.id === secondData.id
).length
if (f1 && f2) {
return true
}
})
} else if (datasOne.length > 0 && datasTwo.length > 0) {
filtered = datasOne.filter(firstData => {
return datasTwo.filter(secondData => firstData.id === secondData.id).length
})
} else if (datasOne.length > 0 && datasThree.length > 0) {
filtered = datasOne.filter(firstData => {
return datasThree.filter(secondData => firstData.id === secondData.id)
.length
})
} else if (datasTwo.length > 0 && datasThree.length > 0) {
filtered = datasTwo.filter(firstData => {
return datasThree.filter(secondData => firstData.id === secondData.id)
.length
})
} else if (datasThree.length > 0) {
filtered = datasThree
} else if (datasTwo.length > 0) {
filtered = datasTwo
} else if (datasOne.length) {
filtered = datasOne
}
console.log(filtered)

1) You can first filter the array which is not empty in arrs.
const arrs = [datasOne, datasTwo, datasThree].filter((a) => a.length);
2) Flatten the arrs array using flat().
arrs.flat()
3) Loop over the flatten array and count the occurrence of all objects using Map
const map = new Map();
for (let o of arrs.flat()) {
map.has(o.id)
? (map.get(o.id).count += 1)
: map.set(o.id, { ...o, count: 1 });
}
4) Loop over the map and collect the result only if it is equal to arrs.length
if (count === arrs.length) result.push(rest);
let datasOne = [
{ id: 1, name: "Gustavo" },
{ id: 2, name: "Ana" },
{ id: 3, name: "Luiz" },
{ id: 8, name: "Alice" },
];
let datasTwo = [
{ id: 1, name: "Gustavo" },
{ id: 3, name: "Luiz" },
{ id: 8, name: "Alice" },
];
let datasThree = [
{ id: 1, name: "Gustavo" },
{ id: 3, name: "Luiz" },
{ id: 2, name: "Ana" },
{ id: 5, name: "Kelly" },
{ id: 4, name: "David" },
];
const arrs = [datasOne, datasTwo, datasThree].filter((a) => a.length);
const map = new Map();
for (let o of arrs.flat()) {
map.has(o.id)
? (map.get(o.id).count += 1)
: map.set(o.id, { ...o, count: 1 });
}
const result = [];
for (let [, obj] of map) {
const { count, ...rest } = obj;
if (count === arrs.length) result.push(rest);
}
console.log(result);
/* This is not a part of answer. It is just to give the output fill height. So IGNORE IT */
.as-console-wrapper { max-height: 100% !important; top: 0; }

Not 100% sure it cover all edge cases, but this might get you on the right track:
function filterArrays(...args) {
const arraysWithData = args.filter((array) => array.length > 0);
const [firstArray, ...otherArrays] = arraysWithData;
return firstArray.filter((item) => {
for (const array of otherArrays) {
if (!array.some((itemTwo) => itemTwo.id === item.id)) {
return false;
}
}
return true;
});
}
Usage:
const filtered = filterArrays(datasOne, datasTwo, datasThree);
console.log(filtered)
I believe the code is fairly readable, but if something is not clear I'm glad to clarify.

function merge(arr){
arr = arr.filter(item=>item.length>0)
const map = {};
arr.forEach(item=>{
item.forEach(obj=>{
if(!map[obj.id]){
map[obj.id]=[0,obj];
}
map[obj.id][0]++;
})
})
const len = arr.length;
const ret = [];
Object.keys(map).forEach(item=>{
if(map[item][0]===len){
ret.push(map[item][1])
}
})
return ret;
}
merge([datasOne,datasTwo,datasThree])

Multiple Dynamic Filters in JavaScript Array

I can't seem to think about how I can overcome this issue where there might be any amount of filters as objects which will help me to filter out the data array.
data = [
{
id: 1,
first_name: 'Colver',
}, {
id: 2,
first_name: 'Brodie',
}, {
id: 3,
first_name: 'Philippa',
}, {
id: 4,
first_name: 'Taite',
}, {
id: 5,
first_name: 'Pierson'
}
];
filters = [
{
field: 'id',
operator: 'between',
value: '2-5'
},
{
field: 'first_name',
operator: 'eq',
value: 'Philippa'
}
];
ngOnInit(): void {
const filteredItems = [];
this.data.forEach(item => {
this.filters.forEach((filter, filterIndex) => {
const itemValue = item[filter.field];
switch (filter.operator) {
case 'eq':
if (itemValue === filter.value) {
filteredItems.push(item);
}
break;
case 'between':
const [firstValue, secondValue] = filter.value.split('-');
if (itemValue > firstValue && itemValue < secondValue) {
filteredItems.push(item);
}
break;
}
});
});
console.log(filteredItems);
}
I basically want the filteredItems to output like below since the id is between 2 and 5 and the first_name is Philippa. But since I'm iterating the filters 2 times both the times items gets pushed to filteredItems.
[{
id: 3,
first_name: 'Philippa',
}]

You could take Array#every and an object for getting the right operator function.
const
data = [{ id: 1, first_name: 'Colver' }, { id: 2, first_name: 'Brodie' }, { id: 3, first_name: 'Philippa' }, { id: 4, first_name: 'Taite' }, { id: 5, first_name: 'Pierson' }],
filters = [{ field: 'id', operator: 'between', value: '2-5' }, { field: 'first_name', operator: 'eq', value: 'Philippa' }],
operators = {
between: (field, range) => {
const [min, max] = range.split('-').map(Number);
return min <= field && field <= max;
},
eq: (field, value) => field === value
},
result = data.filter(o =>
filters.every(({ field, operator, value }) =>
operators[operator](o[field], value)
)
);
console.log(result);

You can perform a reduce operation over the filters array and use Array#filter to remove objects on each iteration.
const data = [
{
id: 1,
first_name: 'Colver',
}, {
id: 2,
first_name: 'Brodie',
}, {
id: 3,
first_name: 'Philippa',
}, {
id: 4,
first_name: 'Taite',
}, {
id: 5,
first_name: 'Pierson'
}
],
filters = [
{
field: 'id',
operator: 'between',
value: '2-5'
},
{
field: 'first_name',
operator: 'eq',
value: 'Philippa'
}
];
const res = filters.reduce((acc,{field,operator,value})=>
acc.filter(o => operator === 'eq' && o[field] === value ||
operator === 'between' && o[field] >= value.split('-')[0]
&& o[field] <= value.split('-')[1]), data);
console.log(res);

Use Array.prototype.every to make sure every filter passes, and if so, push it to the array:
ngOnInit(): void {
const filteredItems = this.data.forEach(item =>
this.filters.every((filter, filterIndex) => {
const itemValue = item[filter.field];
switch (filter.operator) {
case 'eq':
if (itemValue === filter.value) {
return true;
}
break;
case 'between':
const [firstValue, secondValue] = filter.value.split('-');
if (itemValue > firstValue && itemValue < secondValue) {
return true;
}
break;
}
return false;
})
);
console.log(filteredItems);
}

Instead of using
const filteredItems = [];
this.data.forEach(item => {
// [...]
filteresItems.push(item)
// [...]
});
use Array's filter:
const filteredItems = this.data.filter(item => {
// [...]
let match = true; // or false
return match;
});
Taking your whole example, you could use:
function passes(item, filter) {
const itemValue = item[filter.field];
switch (filter.operator) {
case 'eq':
if (itemValue === filter.value) {
return true;
}
case 'between':
const [firstValue, secondValue] = filter.value.split('-');
if (itemValue > firstValue && itemValue < secondValue) {
return true;
}
}
return false;
}
const filteredItems = this.data.filter(
item => this.filters
.map(filter => passes(item, filter))
.every());

Javascript - How to combine all combinations into an array of objects

I have the following array:
[{
name: 'foo',
values: '10,12'
},
{
name: 'bar',
values: 'red,blue'
}]
Using some javascript logic I would like to output the following array:
[{
option1: 10,
option2: 'red'
},
{
option1: 10,
option2: 'blue'
},
{
option1: 12,
option2: 'red'
},
{
option1: 12,
option2: 'blue'
}]
What is the best and correct way to achieve this using javascript?

Lets say your first array is named arr.
var arr = [{
name: 'foo',
values: '10,12'
},
{
name: 'bar',
values: 'red,blue'
}];
var v1 = arr[0].values.split(',');
var v2 = arr[1].values.split(',');
var res = new Array();
for(i in v1){
for(j in v2){
res.push({'option1':v1[i],'option2':v2[j]});
}
}
console.log(res);

Here's an approach that can handle an arbitrary number of objects.
function valuesCrossProduct(input) {
return input.flatMap((current, index, array) => {
let result = [];
let values = current.values.split(',');
for (let v of values) {
for (let i = 0; i < array.length; i++) {
if (i <= index) {
// Skip creating cross products with self (i.e. == index)
// and with previously visited objects (i.e. < index).
continue;
}
let iValues = array[i].values.split(',');
let currentKey = `option${index}`;
let iKey = `option${i}`;
for (let iv of iValues) {
result.push({
[currentKey]: v,
[iKey]: iv,
});
}
}
}
return result;
});
}
let twoElementArray = [{
name: 'foo',
values: '10,12'
},
{
name: 'bar',
values: 'red,blue',
}];
let threeElementArray = [{
name: 'foo',
values: '10,12'
},
{
name: 'bar',
values: 'red,blue',
},
{
name: 'baz',
values: 'wham,bam',
}];
console.log(valuesCrossProduct(twoElementArray));
console.log(valuesCrossProduct(threeElementArray));

Functional for the win.
Note: as it is, this only works for an array of two objects, with any number of values in each, where the first set of values are numbers and the second set are strings, which is what you described above.
const arr = [{
name: 'foo',
values: '10,12'
},
{
name: 'bar',
values: 'red,blue'
}];
const values = arr
.map(o => o.values.split(','))
.reduce((cur, next) => {
return cur.map(c => {
return next.map(n => {
return {
option1: parseInt(c),
option2: n
};
});
}).flat();
});
console.log(values);

If you need generic approach to get possible options from various values.
const options = data => {
let sets = [[]];
data.forEach(({ values }, i) => {
const new_set = [];
values.split(",").forEach(value => {
new_set.push(
Array.from(sets, set => [...set, [`option${i + 1}`, value]])
);
});
sets = new_set.flatMap(set => set);
});
return sets.map(set => Object.fromEntries(set));
};
const data = [
{
name: "foo",
values: "10,12"
},
{
name: "bar",
values: "red,blue,green"
},
{
name: "test",
values: "top,bottom"
}
];
console.log(options(data));

Merge arrays in JS

Suppose I have the following arrays:
var first = [
{ id: 1, name: 'first' },
{ id: 2, name: 'second' },
{ id: 3, name: 'third' }
]
var second = [
{ id: 2, field: 'foo2' },
{ id: 3, field: 'foo3' },
{ id: 4, field: 'foo4' }
]
var third = [
{ id: 2, data: 'some2' },
{ id: 5, data: 'some5' },
{ id: 6, data: 'some6' }
]
I want to merge them to get the following result:
var result = [
{ id: 1, name: 'first', field: undefined, data: undefined },
{ id: 2, name: 'second', field: 'foo2', data: 'some2' },
{ id: 3, name: 'third', field: 'foo3', data: undefined },
{ id: 4, name: undefined, field: 'foo4', data: undefined },
{ id: 5, name: undefined, field: undefined, data: 'some5' },
{ id: 6, name: undefined, field: undefined, data: 'some6' }
]
How could I do it with JavaScript?

You should get all existed keys and after create new Objects with fill "empty" keys:
function mergeArrays(){
var keys = {};
//save all existed keys
for(var i=arguments.length;--i;){
for(var j=arguments[i].length;--j;){
for(var key in arguments[i][j]){
keys[key] = true;
}
}
}
var res = [];
for(var i=arguments.length;--i;){
for(var j=arguments[i].length;--j;){
//set clone of object
var clone = JSON.parse(JSON.stringify(arguments[i][j]));
for(var key in keys){
if(!(key in clone)){
clone[key] = undefined;
}
}
res.push(clone);
}
}
return res;
}
https://jsfiddle.net/x3b0tk3g/

There is no simple solution for what you want. Here is my suggestion.
var first = [
{ id: 1, name: 'first' },
{ id: 2, name: 'second' },
{ id: 3, name: 'third' }
]
var second = [
{ id: 2, filed: 'foo2' },
{ id: 3, field: 'foo3' },
{ id: 4, field: 'foo4' }
];
var third = [
{ id: 2, data: 'some2' },
{ id: 4, data: 'some4' },
{ id: 6, data: 'some6' }
];
var result = {};
first.concat(second,third).forEach(function(item){
var id = item.id;
var row = result[id];
if(!row){
result[id] = item;
return;
}
for(var column in item){
row[column] = item[column];
}
});
var finalResult = Object.keys(result).map(function(id){
return result[id];
});
console.log(finalResult);

fiddle: http://jsfiddle.net/bs20jvnj/2/
function getByProperty(arr, propName, propValue) {
for (var i = 0; i < arr.length; i++) {
if (arr[i][propName] == propValue) return arr[i];
}
}
var limit = first.length + second.length + third.length;
var res = [];
for (var i = 1; i < limit; i++) {
var x = $.extend({}, getByProperty(first, "id", i), getByProperty(second, "id", i), getByProperty(third, "id", i));
console.log(x["id"]);
if (x["id"] === undefined) x["id"] = i;
res.push(x);
}
console.log(res);

There's probably a shorter way to solve this, but this covers all the steps, including ensuring that there are default properties that are undefined if not found. It also takes any number of input arrays, and you can specify what default keys you require if they're not already covered by the keys in the existing objects, so pretty future-proof for your needs.
// merges the key/values of two objects
function merge(a, b) {
var key;
if (a && b) {
for (key in b) {
if (b.hasOwnProperty(key)) {
a[key] = b[key];
}
}
}
return a;
}
function concatenate() {
var result = [];
var args = arguments[0];
for (var i = 0, l = args.length; i < l; i++) {
result = result.concat(args[i]);
}
return result;
}
// return a default object
function getDefault() {
return {
id: undefined,
name: undefined,
data: undefined,
field: undefined
};
}
// loop over the array and check the id. Add the id as a key to
// a temporary pre-filled default object if the key
// doesn't exist, otherwise merge the existing object and the
// new object
function createMergedArray(result) {
var temp = {};
var out = [];
for (var i = 0, l = result.length; i < l; i++) {
var id = result[i].id;
if (!temp[id]) temp[id] = getDefault();
merge(temp[id], result[i]);
}
// loop over the temporary object pushing the values
// into an output array, and return the array
for (var p in temp) {
out.push(temp[p]);
}
return out;
}
function mergeAll() {
// first concatenate the objects into a single array
// and then return the results of merging that array
return createMergedArray(concatenate(arguments));
}
mergeAll(first, second, third);
DEMO