Merge arrays and combine the values - javascript

I am trying to combine an array of objects while removing duplicates based of a particular value, in this case it's id. I want to merge the other properties in each of the objects.
This is what I have:
var myArray = [
{
id : 1,
rendering : 0,
completed : 1
},
{
id : 2,
rendering : 0,
completed : 1
},
{
id : 3,
rendering : 0,
completed : 1
},
{
id : 1,
rendering : 1,
completed : 0
},
{
id : 2,
rendering : 1,
completed : 0
},
{
id : 3,
rendering : 1,
completed : 0
},
]
This is what I want :
var myDesiredArray = [
{
id : 1,
rendering: 1,
completed: 1
},
{
id : 2,
rendering: 1,
completed: 1
},
{
id : 3,
rendering: 1,
completed: 1
},
]
I'd be happy with straight javascript or underscore/lodash. Any suggestions would be greatly appreciated.

Using underscore, here's one way to do it
Define a sum function
function sum(numbers) {
return _.reduce(numbers, function(result, current) {
return result + parseFloat(current);
}, 0);
}
Then groupby over id and pluck needed values and apply sum over them.
_.chain(myArray )
.groupBy("id")
.map(function(value, key) {
return {
id: key,
rendering : sum(_.pluck(value, "rendering")),
completed: sum(_.pluck(value, "completed"))
}
})
.value();

function merge(arr) {
var uniqItems = arr.reduce(function(memo, item) {
if (!memo[item.id]) {
memo[item.id] = item;
} else {
Object.keys(item).forEach(function(k) {
if (item[k]) { memo[item.id][k] = item[k]; }
});
}
return memo;
}, {});
return Object.keys(uniqItems).map(function(k) {
return uniqItems[k];
});
}
merge(myArray); // => myDesiredArray

There is multiple way to do, but as you want to check uniqueness, the easiest way would be to use a temporary map, indexed by your ids, on which you can accumulate the values of the other properties.
When the accumulation is done, convert the Map to a straight array, et voila.
You would do it like so:
var array; // defined elsewhere
var tmp = {}; // temporary map
// accumulate the properties in the map
array.forEach(function(elt) {
if (tmp[elt.id] == null)
tmp[elt.id] = elt
else {
tmp[elt.id].prop += elt.prop;
// (...) do the accumulation here
}
});
// then convert this map to an array by iterating on the ids
Object.keys(tmp).map(function(id) { return tmp[id]; })

Pure JS solution
The first thing you should do is use a map for fast lookup:
var map = {};
myArray.forEach(function(item){
var mapItem = map[item.id] || {
id : item.id,
rendering : 0,
completed : 0
}
mapItem.rendering += item.rendering;
mapItem.completed += item.completed;
map[item.id] = mapItem;
});
Then you can convert the map back to an array:
var myDesiredArray = [];
for (var id in map) {
myDesiredArray.push(map[id]);
}

Here is another vanilla js version using a functional approach:
myArray.reduce(function(prev, cur) {
if (prev[cur.id]) {
prev[cur.id].rendering += cur.rendering;
prev[cur.id].completed += cur.completed;
} else {
prev[cur.id] = cur;
}
return prev;
}, []).filter(function(val) {
return val;
});

Solution with less loop possible
function myMerge(myArray) {
var temp = {},
myDesiredArray = [];
for (var i = 0; i < myArray.length; ++i) {
var elem = myArray[i];
if (!temp[elem.id]) {
temp[elem.id] = {
'id': elem.id,
'rendering': elem.rendering,
'completed': elem.completed,
};
myDesiredArray.push(temp[elem.id])
}
temp[elem.id].rendering += elem.rendering;
temp[elem.id].completed += elem.completed;
}
return myDesiredArray;
}

Related

Optimize solution for faster execution - NodeJs

I am trying optimize a solution which is used to group the objects based on value present in another array (mapping ) which is written is NodeJS.
function workerFunction(report) {
const groupedArray = []
const granularityKey = 'Month'
const mapping = ['TestField1', 'TestField2'] //will be dynamic based on json input
let activeIIndex = 0;
while (activeIIndex < report.length) {
const index = groupedArray
.findIndex(item => mapping
.every((column) => item[column] === report[activeIIndex][column]))
if (index === -1) {
report[activeIIndex][report[activeIIndex][granularityKey]] = report[activeIIndex]['Cost']
groupedArray.push(report[activeIIndex])
} else {
groupedArray[index][report[activeIIndex][granularityKey]] = report[activeIIndex]['Cost']
}
activeIIndex++;
}
return groupedArray
}
The input to the workerFunction(report) will look like this (usually the array size will be above 300k),
[
{
"TestField1":"value",
"TestField2":"value2",
"Cost":12.5555,
"Month":10
},
{
"TestField1":"value3",
"TestField2":"value4",
"Cost":142.5555,
"Month":10
},
{
"TestField1":"value6",
"TestField2":"value4",
"Cost":15.87,
"Month":10
},
{
"TestField1":"value3",
"TestField2":"value4",
"Cost":16.5555,
"Month":11
}
]
The expected output after passing this json object through workerFunction will be
[
{
"TestField1":"value",
"TestField2":"value2",
"Cost":12.5555,
"Month":10,
"10":12.5555
},
{
"TestField1":"value3",
"TestField2":"value4",
"Cost":142.5555,
"Month":10,
"10":142.5555,
"11":16.5555
},
{
"TestField1":"value6",
"TestField2":"value4",
"Cost":15.87,
"Month":10,
"10":15.87
},
]

restructure json based on parent

I am studying the use of reduce in javascript, and I am trying to restructure an Array of Objects in a generic way - need to be dynamic.
flowchart - i get totaly lost
I started with this through.
Every ID becomes a Key.
Every PARENT identifies which Key it belongs to.
i have this:
const in = [
{
"id": "Ball",
"parent": "Futebol"
},
{
"id": "Nike",
"parent": "Ball"
},
{
"id": "Volley",
"parent": null
}
]
i want this
out = {
"Futebol": {
"Ball": {
"Nike": {}
}
},
"Volley": {}
}
i try it - and i had miserably failed.
const tree = require('./mock10.json')
// Every ID becomes a Key.
// Every PARENT identifies which Key it belongs to.
const parsedTree = {}
tree.reduce((acc, item) => {
if (parsedTree.hasOwnProperty(item.parent)){
if (parsedTree[`${item.parent}`].length > 0) {
parsedTree[`${item.parent}`][`${item.id}`] = {}
} else {
parsedTree[`${item.parent}`] = { [`${item.id}`]: {} }
}
} else {
// i get lost in logic
}
}, parsedTree)
console.log(parsedTree)
Got a working code for you, feel free to ask me about the implementation
Hope it helps :)
const arrSample = [
{
"id": "Ball",
"parent": "Futebol"
},
{
"id": "Nike",
"parent": "Ball"
},
{
"id": "Volley",
"parent": null
}
]
const buildTree = (arr) => {
return arr.reduce(([tree, treeMap], { id, parent }) => {
const val = {}
treeMap.set(id, val)
if (!parent) {
tree[id] = val
return [tree, treeMap]
}
if (!treeMap.has(parent)) {
const parentVal = { [id]: val }
treeMap.set(parent, parentVal)
tree[parent] = parentVal
return [tree, treeMap]
}
const newParentValue = treeMap.get(parent)
newParentValue[id] = val
treeMap.set(parent, newParentValue)
return [tree, treeMap]
}, [{}, new Map()])
}
const [result] = buildTree(arrSample)
console.log(JSON.stringify(result, 0, 2))
You could use reduce method for this and store each id on the first level of the object. This solution will work if the objects in the array are in the correct order as in the tree structure.
const data = [{"id":"Futebol","parent":null},{"id":"Ball","parent":"Futebol"},{"id":"Nike","parent":"Ball"},{"id":"Volley","parent":null}]
const result = data.reduce((r, { id, parent }) => {
if (!parent) {
r[id] = {}
r.tree[id] = r[id]
} else if (r[parent]) {
r[parent][id] = {}
r[id] = r[parent][id]
}
return r
}, {tree: {}}).tree
console.log(result)
If reduce solution is just an option, you can try this way:
var input = [
{
"id": "Ball",
"parent": "Futebol"
},
{
"id": "Nike",
"parent": "Ball"
},
{
"id": "Volley",
"parent": null
}
];
var output = {};
input.forEach(item => {
var temp = input.find(x => x.id === item.parent);
if (temp) {
temp[item.id] = {};
}
});
input = input.filter(item => !input.find(x => x.hasOwnProperty(item.id)));
input.forEach(item => {
if (!item.parent) {
output[item.id] = {};
} else {
for (var [id, value] of Object.entries(item)) {
if (typeof value === 'object') {
output[item.parent] = { [item.id]: { id: {} } };
}
}
}
})
console.log(output);
I have tried many things, but none works if we use an Array.prototype.reduce
As there are missing parents, and the elements are out of order, plus the fact that there can be an infinity of levels, I really do not believe that this question can be resolved with a simple reduce
This code should work whatever the cases :
- if all parents are not declared
- if there are infinitely many levels
- if they are in disorder
const origin =
[ { id: 'Ball', parent: 'Futebol' }
, { id: 'Nike', parent: 'Ball' }
, { id: 'Volley', parent: null }
, { id: 'lastOne', parent: 'level4' } // added
, { id: 'level4', parent: 'Nike' } // added
, { id: 'bis', parent: 'Nike' } // added
];
const Result = {} // guess who ?
, Parents = [] // tempory array to keep parents elements address by key names
;
let nbTodo = origin.length // need this one to verify number of elements to track
;
// set all the first levels, add a todo flags
origin.forEach(({id,parent},i,ori)=>
{
ori[i].todo = true // adding todo flag
if (parent===null)
{
Result[id] = {} // new first level element
ori[i].todo = false // one less :)
nbTodo--
Parents.push(({ref:id,path:Result[id]}) ) // I know who you are!
}
else if (origin.filter(el=>el.id===parent).length===0) // if he has no parent...
{
Result[parent] = {} // we create it one
Parents.push({ref:parent,path:Result[parent]} )
}
})
// to put the children back in their parents' arms
while(nbTodo>0) // while there are still some
{
origin.forEach(({id,parent,todo},i,ori)=> // little by little we find them all
{
if(todo) // got one !
{
let pos = Parents.find(p=>p.ref===parent) // have parent already been placed?
if(pos)
{
ori[i].todo = false // to be sure not to repeat yourself unnecessarily
nbTodo-- // one less :)
pos.path[id] = {} // and voila, parentage is done
Parents.push(({ref:id,path:pos.path[id]}) ) // he can now take on the role of parent
}
}
})
}
for (let i=origin.length;i--;) { delete origin[i].todo } // remove todo flags
console.log( JSON.stringify(Result, 0, 2) )
.as-console-wrapper { max-height: 100% !important; top: 0; }
I finaly made this one, based on this previous on, and done with a first step by a reduce...
to by pass the Array of Parents, I made a recursive function for searching each parent elements thru the levels of parsedTree result.
here is the code:
const Tree =
[ { id: 'Ball', parent: 'Futebol' }
, { id: 'Nike', parent: 'Ball' }
, { id: 'Volley', parent: null }
, { id: 'lastOne', parent: 'level4' } // added
, { id: 'level4', parent: 'Nike' } // added
, { id: 'bis', parent: 'Nike' } // added
];
const parsedTree = Tree.reduce((parTree, {id,parent},i ) => {
Tree[i].todo = false
if (parent===null)
{ parTree[id] = {} }
else if (Tree.filter(el=>el.id===parent).length===0) // if he has no parent...
{ parTree[parent] = { [id]: {} } }
else
{ Tree[i].todo = true }
return parTree
}, {})
function parsedTreeSearch(id, part) {
let rep = null
for(let kId in part) {
if (kId===id)
{ rep = part[kId] }
else if (Object.keys(part[kId]).length)
{ rep = parsedTreeSearch(id, part[kId]) }
if (rep) break
}
return rep
}
while (Boolean(Tree.find(t=>t.todo))) {
Tree.forEach(({id,parent,todo},i)=>{ // little by little we find them all
if (todo) {
let Pelm = parsedTreeSearch(parent, parsedTree)
if (Boolean(Pelm)) {
Pelm[id] = {}
Tree[i].todo = false
} } }) }
for (let i=Tree.length;i--;) { delete Tree[i].todo } // remove todo flags
console.log( JSON.stringify( parsedTree ,0,2))
.as-console-wrapper { max-height: 100% !important; top: 0; }

How to pick data from array and create a single Object from it?

I want to create a single object from an array of objects. Please refer the code provided.
Here's the input array
let queryArr = [
{
query: {
filter: {
term: {
search: 'complete',
}
}
}
},
{
query: {
notFilter: {
term: {
search: 'failed',
}
}
}
},
{
query: {
bool: {
term: {
search: 'complete',
}
}
}
}
]
The expected output
let oneQuery = {query: {
bool: { ... },
filter: { ... },
notFilter: { ... } // data from respective array object key
}};
The function I wrote
function createQuery(arr){
for(let i = 0; i < arr.length; i++){
if(Object.keys(arr[i].query === 'bool')){
oneQuery.query.bool = arr[i].query.bool;
}
if(Object.keys(arr[i].query === 'filter')){
oneQuery.query.filter = arr[i].query.filter;
}
if(Object.keys(arr[i].query === 'notFilter')){
oneQuery.query.notFilter = arr[i].query.notFilter;
}
}
return oneQuery;
}
createQuery(queryArr);
The output I'm getting:
query: {
bool: { ... },
filter: undefined,
notFilter: undefined
}
I don't get what I'm doing wrong here. A solution using reduce or map will be preferred.
Use Array.map() to get an array with the contents of each query property, then spread into Object.assign() to combine to a single object:
const queryArr = [{"query":{"filter":{"term":{"search":"complete"}}}},{"query":{"notFilter":{"term":{"search":"failed"}}}},{"query":{"bool":{"term":{"search":"complete"}}}}];
const createQuery = (arr) => ({
query: Object.assign({}, ...queryArr.map(({ query }) => query))
});
console.log(createQuery(queryArr));
To fix your code, initialize the query item, and get the 1st key from each item in the array - arr[i].query)[0]:
const queryArr = [{"query":{"filter":{"term":{"search":"complete"}}}},{"query":{"notFilter":{"term":{"search":"failed"}}}},{"query":{"bool":{"term":{"search":"complete"}}}}]
function createQuery(arr){
const oneQuery = { query: {} };
for(let i = 0; i < arr.length; i++){
if(Object.keys(arr[i].query)[0] === 'bool'){
oneQuery.query.bool = arr[i].query.bool;
}
if(Object.keys(arr[i].query)[0] === 'filter'){
oneQuery.query.filter = arr[i].query.filter;
}
if(Object.keys(arr[i].query)[0] === 'notFilter'){
oneQuery.query.notFilter = arr[i].query.notFilter;
}
}
return oneQuery;
}
console.log(createQuery(queryArr));
You problem seems to be this line
Object.keys(arr[i].query === 'filter')
This evaluates to Object.keys(true) or Object.keys(false)
Use reduce
queryArr.reduce( (acc, c) => (
acc[ Object.keys(c.query)[0] ] = Object.values(c.query)[0], //set the first key and value to accumulator
acc ), //return the accumulator
{}); //initialize accumulator to {}

Recursively find keys on an object

I have a javascript object structured like this;
brand: {
group: {
subGroup: {
items: []
},
otherSub: {
items: []
}
}
}
Given an array of keys ['brand', 'group', 'newGroup', 'newSubGroup'] I want to split the keys into found and missing keys. So for the structure above I should get back;
present = ['brand', 'group']
missing = ['newGroup', 'newSubGroup']
I'm using ES6 and have lodash available, but struggling to find a clean way to produce this.
This is not to just check existence, it's recursively find the keys and return those present and the remaining ones.
Here's a pretty sketchy way that works.
const find = (keys, obj) => {
const string = JSON.stringify(obj);
return keys.reduce(({ present, missing }, key) => {
const match = string.match(new RegExp(`"${key}":`));
if (match) {
present.push(key);
} else {
missing.push(key);
}
return { present, missing };
}, { present: [], missing: [] });
}
You can use this function made for you ;)
var getAttrs = function(obj) {
return [].concat.apply([], Object.keys(obj).map(function (key) {
var results = [key]
if (typeof obj[key] === 'object') {
Array.prototype.push.apply(results, getAttrs(obj[key]))
}
return results
}))
}
It return the list of properties and children properties.
getAttrs({brand: {
group: {
subGroup: {
items: []
},
otherSub: {
items: []
}
}
}})
> ["brand", "group", "subGroup", "items", "otherSub", "items"]
And you can use it like so:
var lookingFor = ['brand', 'group', 'newGroup', 'newSubGroup']
var existings = getAttrs(obj)
var missings = []
var presents = []
lookingFor.forEach(attr => {
if (existings.indexOf(attr) === -1) {
missings.push(attr)
} else {
presents.push(attr)
}
})
I wrote a function to recursively get unique keys from a nested object, then filtered the array of all the keys you mentioned checking which were present in the result of my function.
var thisObject = {
brand: {
group: {
subGroup: {
items: []
},
otherSub: {
items: []
}
}
}
};
var arr_full = ['brand', 'group', 'newGroup', 'newSubGroup'] ;
var key_array = [];
function addToKeyArray( key_array, object ){
for( var key in object ){
// only get unique keys
if( key_array.indexOf( key ) === -1 ){
key_array.push( key );
}
// concat the result of calling this function recurrsively on object[key]
key_array.concat( addToKeyArray( key_array, object[key] ) );
}
return key_array;
}
var test = addToKeyArray( [], thisObject );
var missing = arr_full.filter( function( el ) {
return test.indexOf( el ) < 0;
});
console.log( test );
console.log( missing )
You can create recursive function using for...in loop inside another function and return object as result..
var obj = {"brand":{"group":{"subGroup":{"items":[]},"otherSub":{"items":[]}}}}
var keys = ['brand', 'group', 'newGroup', 'newSubGroup'] ;
function findKeys(data, keys) {
keys = keys.slice();
function findPresent(data, keys) {
var result = []
for(var i in data) {
if(typeof data[i] == 'object') result.push(...findPresent(data[i], keys))
var index = keys.indexOf(i);
if(index != -1) result.push(...keys.splice(index, 1))
}
return result
}
return {present: findPresent(data, keys), missing: keys}
}
console.log(findKeys(obj, keys))
To keep things clean and readable you can use "for in", inside a nested function for your recursion.
function recur(obj) {
let preMiss = {
present: [],
missing: []
}
let root = traverse => {
for (let key in traverse) {
if (Array.isArray(traverse[key].items)) {
preMiss.missing.push(key);
}
if (typeof traverse[key] === 'object' && !Array.isArray(traverse[key].items)) {
preMiss.present.push(key);
root(traverse[key])
}
}
}
root(obj);
return preMiss;
}
const object = {
brand: {
group: {
subGroup: {
items: []
},
otherSub: {
items: []
}
}
}
}
console.log(Object.entries(recur(object)));
var toFind = ['brand', 'group', 'newGroup', 'newSubGroup'],
found = [];
var o = {
brand: {
group: {
subGroup: {
items: []
},
otherSub: {
items: []
}
}
}
}
//called with every property and its value
function process(key,value) {
var i = toFind.indexOf(key);
if(i !== -1){
found.push(key);
toFind.splice(i, 1);
}
}
function traverse(o,func) {
if(!toFind.length) return;
for (var i in o) {
func.apply(this,[i,o[i]]);
if (o[i] !== null && typeof(o[i])=="object") {
//going one step down in the object tree!!
traverse(o[i],func);
}
}
}
traverse(o,process);
console.log(found); // present
console.log(toFind); // absent
Traverse method taken from https://stackoverflow.com/a/722732/1335165
Even though this question is a bit older, I want to present a rather short solution to the problem.
const recursivelyGetKeys = obj => Object.keys(obj).map(key => typeof obj[key] === 'object'
? [...recursivelyGetKeys(obj[key]), key] : [key]).reduce((p, c) => [...p, ...c], [])
This function will return all keys in the object, so a call to the array arr with
const arr = {
brand: {
group: {
subGroup: {
items: []
},
otherSub: {
items: []
}
}
}
}
will output:
const keys = recursivelyGetKeys(arr) // = ["items", "subGroup", "items", "otherSub", "group", "brand"]
Now to find the intersection set of this and find = ['brand', 'group', 'newGroup', 'newSubGroup'], do:
const found = keys.filter(key => find.some(val === key))
const missing = keys.filter(key => find.every(val !== key))

Split array into new array based on property occurences

I have an array of objects that I would like to turn into an array (or array-like) object where the keys are the unique values for that given property (something like SQL group by).
fiddle:
var obj = [
{
"ClaimId":"111",
"DrugName":"AMBIEN CR",
"PatientId":1571457415
},
{
"ClaimId":"222",
"DrugName":"AMBIEN CR",
"PatientId":1571457415
},
{
"ClaimId":"333",
"DrugName":"LOTREL",
"PatientId":1571457415
},
{
"ClaimId":"444",
"DrugName":"METHYLPREDNISOLONE",
"PatientId":1571457415
},
{
"ClaimId":"555",
"DrugName":"CYMBALTA",
"PatientId":1513895252
},
{
"ClaimId":"666",
"DrugName":"CYMBALTA",
"PatientId":1513895252
},
{
"ClaimId":"777",
"DrugName":"CYMBALTA",
"PatientId":1513895252
},
{
"ClaimId":"888",
"DrugName":"CYMBALTA",
"PatientId":1513895252
},
{
"ClaimId":"147503879TMQ",
"DrugName":"CYMBALTA",
"PatientId":1513895252
},
{
"ClaimId":"999",
"DrugName":"CYMBALTA",
"PatientId":1513895252
}
]
function splitBy(data, prop) {
var returnObj = {};
var returnArray = [];
$.each(data, function (ix, val) {
if (returnObj[val[prop]] === undefined) {
returnObj[val[prop]] = [];
returnObj[val[prop]].push(val);
}
});
console.log(returnObj);
}
splitBy(obj,'PatientId');
In the fiddle you can see that I get the keys of the array like I want (the two unique values in the PatientId property) but I only get the first value. I understand that's because once the key is no longer undefined, then this check isn't ran, but I couldn't figure out quite how to do it and this is as close as I got. How can I do this with one iteration over this collection?
I only get the first value.
That's because you only push the first value - when there had been no key. Change the
if (returnObj[val[prop]] === undefined) {
returnObj[val[prop]] = [];
returnObj[val[prop]].push(val);
}
to
if (returnObj[val[prop]] === undefined) {
returnObj[val[prop]] = [];
}
returnObj[val[prop]].push(val);
jsFiddle Demo
You almost had it, but you forgot the else clause for once the key existed
if (returnObj[val[prop]] === undefined) {
returnObj[val[prop]] = [];
returnObj[val[prop]].push(val);
}else{
returnObj[val[prop]].push(val);
}

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