Merge items from two arrays based on matching ID - javascript

I have a data object like this :
{
"data1": [
[
"ID",
"name",
"Birthday"
],
[
"10",
"thomas",
"1992-03-17"
],
[
"11",
"Emily",
"2000-03-03"
]
],
"data2": [
[
"Balance",
"ID"
],
[
"$4500",
"10"
],
[
"$1500",
"13"
]
]
}
It contains two arrays data1 and data2.
The first row in each array is the name of the columns and the rest of the rows have the data (think of it like a table).
I want to compare the ID field in both arrays and if the IDs match then the final output will contain a column Balance with the balance corresponding to that ID and if the IDs don't match then the Balance will be $0.
Expected output:
{
"output": [
[
"ID",
"name",
"Birthday",
"Balance"
],
[
"10",
"thomas",
"1992-03-17",
"$4500" //ID 10 matched so the balance added here
],
[
"11",
"Emily",
"2000-03-03",
"0" //0 bcoz the ID 11 is not there in data2 array
]
]
}
I find this challenging to accomplish. Think of it like a LEFT-JOIN in MySQL.
I referred to this solution but it doesn't work in my case as I don't have the keys in my response.
EDIT: I also need to join the other fields as well.

You can use Array.prototype.map(), find, filter, slice, reduce, concat, includes and Object.assign().
This solution:
Handles arbitrary ordering of the items. The order is read from the headers.
Appends a Balance field only if there is one present in data2.
Joins all other fields (requested by OP, see comments below).
Takes default values as an input and uses them if the data is not present in data1 and data2.
function merge({ data1, data2 }, defaults) {
// get the final headers, add/move 'Balance' to the end
const headers = [...data1[0].filter(x => x !== 'Balance')]
.concat(data2[0].includes('Balance') ? ['Balance'] : []);
// map the data from data1 to an array of objects, each key is the header name, also merge the default values.
const d1 = data1.slice(1)
.map(x => x.reduce((acc, y, i) => ({ ...defaults, ...acc, [data1[0][i]]: y }), {}));
// map the data from data2 to an array of objects, each key is the header name
const d2 = data2.slice(1)
.map(x => x.reduce((acc, y, i) => ({ ...acc, [data2[0][i]]: y }), {}));
// combine d1 and d2
const output = d1.map((x, i) => { // iterate over d1
// merge values from d2 into this value
const d = Object.assign(x, d2.find(y => y['ID'] === x['ID']));
// return an array ordered according to the header
return headers.map(h => d[h]);
});
return { output: [headers, ...output] };
}
const test0 = {
data1: [[ "ID","name","Birthday","other"],["10","thomas","1992-03-17","empty"],["11","Emily","2000-03-03","empty"]],
data2: [["other", "ID", "Balance", "city"],["hello", "10", "$4500", "New York"],["world", "10","$8","Brazil"]]
};
const test1 = {
data1: [["ID","name","Birthday"],["10","thomas","1992-03-17"],["11","Emily","2000-03-03"]],
data2: [["other","ID"],["x","10"],["y","11"]]
};
console.log(merge(test0, { Balance: '$0' }));
console.log(merge(test1, { Balance: '$0' }));

const KEY_ID = "ID";
var data = {
"data1": [
[ "ID", "name", "Birthday" ],
[ "10", "thomas", "1992-03-17" ],
[ "11", "Emily", "2000-03-03" ]
],
"data2": [
[ "Balance", "ID" ],
[ "$4500", "10" ],
[ "$1500", "13" ]
]
}
var merged = Object.keys(data).map(function (key) {
var tmp = data[key].slice();
var heads = tmp.shift();
return tmp.map(function (item) {
var row = {};
heads.forEach(function (head, i) {
row[head] = item[i];
});
return row;
});
}).flat().reduce(function (acc, row) {
var found = acc.find(function (item) {
return row[KEY_ID] === item[KEY_ID];
})
if (!found) {
found = row;
acc.push(found);
} else {
Object.keys(row).forEach(function (head) {
found[head] = row[head];
});
}
return acc;
}, []);
console.log(merged);
This solution is scalable: if you add properties, it will scale the new format.

let a = { "data1": [ ... ],"data2": [ ...] }
let r = a.data1.reduce((r,u,i)=>{
if(i !== 0)
{
let entry = a.data2.filter((a)=> a[1]===u[0])
r.push([...u,entry.length ? entry[0][0] : 0])
}
return r
},[[
"ID",
"name",
"Birthday",
"Balance"
]])

You could abstract all table operations into a class-like:
function Table(array) {
const [head, ...values] = array;
const Entry =(entry) => ({
get(key) { return entry[ head.indexOf(key) ]; },
set(key, value) { entry[ head.indexOf(key) ] = value; }
});
return {
index(name) {
const result = {};
for(const value of values)
result[ value[ head.indexOf(name) ] ] = Entry(value);
return result;
},
*[Symbol.iterator]() {
for(const row of values)
yield Entry(row);
},
addRow(key) { head.push(key); }
};
}
Usable as:
const users = Table(obj.data1);
const balances = Table(obj.data2);
const balanceByID = balance.index("ID");
users.addRow("Balance");
for(const user of users)
user.set("Balance", balanceByID[ user.get("ID") ].get("Balance"));

Related

Create an array of objects based on an object if one or more properties have multiple values differentiated by a comma

i'm trying to duplicate objects based on two properties that have multiple values differentiated by a comma.
For example:
I have an object
const obj = {
id: 1
date: "2021"
tst1: "111, 222"
tst2: "AAA, BBB"
}
And I would like the result to be an array of 2 objects in this case (because there are 2 values in tst1 OR tst2, these 2 properties will always have the same nr of values differentiated by a comma)
[{
id: 1,
date: "2021",
tst1: "111",
tst2: "AAA",
},
{
id: 1,
date: "2021",
tst1: "222",
tst2: "BBB",
}]
What I tried is this:
I created a temporary object
const tempObject = {
id: obj.id,
date: obj.date,
}
And then I would split and map the property that has multiple values, like this:
cont newObj = obj.tst1.split(",").map(function(value) {
let finalObj = {}
return finalObj = {
id: tempObject.id,
date: tempObject.date,
tst1: value,
})
And now, the newObj is an array of objects and each object contains a value of tst1.
The problem is I still have to do the same for the tst2...
And I was wondering if there is a simpler method to do this...
Thank you!
Here is an example that accepts an array of duplicate keys to differentiate. It first maps them to arrays of entries by splitting on ',' and then trimming the entries, then zips them by index to create sub-arrays of each specified property, finally it returns a result of the original object spread against an Object.fromEntries of the zipped properties.
const mapDuplicateProps = (obj, props) => {
const splitProps = props.map((p) =>
obj[p].split(',').map((s) => [p, s.trim()])
);
// [ [[ 'tst1', '111' ], [ 'tst1', '222' ]], [[ 'tst2', 'AAA' ], [ 'tst2', 'BBB' ]] ]
const dupeEntries = splitProps[0].map((_, i) => splitProps.map((p) => p[i]));
// [ [[ 'tst1', '111' ], [ 'tst2', 'AAA' ]], [[ 'tst1', '222' ], [ 'tst2', 'BBB' ]] ]
return dupeEntries.map((d) => ({ ...obj, ...Object.fromEntries(d) }));
};
const obj = {
id: 1,
date: '2021',
tst1: '111, 222',
tst2: 'AAA, BBB',
};
console.log(mapDuplicateProps(obj, ['tst1', 'tst2']));
Not sure if that's what you're searching for, but I tried making a more general use of what you try to do:
const duplicateProperties = obj => {
const properties = Object.entries(obj);
let acc = [{}];
properties.forEach(([key, value]) => {
if (typeof value === 'string' && value.includes(',')) {
const values = value.split(',');
values.forEach((v, i) => {
if (!acc[i]) {
acc[i] = {};
}
acc[i][key] = v.trim();
});
} else {
acc.forEach(o => o[key] = value);
}
});
return acc;
};
const obj = {
id: 1,
date: '2021',
tst1: '111, 222',
tst2: 'AAA, BBB',
};
console.log(duplicateProperties(obj));
You could start by determining the length of the result using Math.max(), String.split() etc.
Then you'd create an Array using Array.from(), returning the correct object for each value of the output index.
const obj = {
id: 1,
date: "2021",
tst1: "111, 222",
tst2: "AAA, BBB",
}
// Determine the length of our output array...
const length = Math.max(...Object.values(obj).map(s => (s + '').split(',').length))
// Map the object using the relevant index...
const result = Array.from({ length }, (_, idx) => {
return Object.fromEntries(Object.entries(obj).map(([key, value]) => {
const a = (value + '').split(/,\s*/);
return [key, a.length > 1 ? a[idx] : value ]
}))
})
console.log(result)
.as-console-wrapper { max-height: 100% !important; }

array of arrays conversion in Javascript

I need to create an array of array.
It is worth noting that the database is very large and that if any attribute does not have a corresponding value, it sends an empty string. I've tried with map and reduce but I wasn't successful:
Any help will be appreciated.
Below I show an example of the expected output:
outputExpected = [
["id", 1, 2],
["name", "name1", "name2"],
["price", 6.95, 998.95],
["promoPrice", 5.91, 333.91],
["category", "test1 | test2", "test3 | test4"],
]
Any way to solve this problem performatically?
this is my code:
let arrayObj = [{
"id": 1,
"name": "name1",
"price": 6.95,
"promoPrice": 5.91,
"category": ["test1, test2"]
},
{
"id": 2,
"name": "name2",
"price": 998.95,
"promoPrice": 333.91,
"category": ["test3, test4"]
}
]
const headers = ["id", "name", "price", "promoPrice", "category"]
const result1 = headers.concat(arrayObj.map((obj) => {
return headers.reduce((arr, key) => {
arr.push(obj[key]) return arr;
}, [])
}))
console.log(result1)
Reduce the array to a Map. On each iteration convert the object to an array of [key, value] pairs using Object.entries(). Use Array.forEach() to iterate the entries and add them to the map. Convert the Map's values iterator to an array using Array.from():
const arr = [{"id":1,"name":"name1","price":6.95,"promoPrice":5.91,"category":["test1", "test2"]},{"id":2,"name":"name2","price":998.95,"promoPrice":333.91,"category":["test3", "test4"]}]
const result = Array.from(arr.reduce((acc, o) => {
Object.entries(o)
.forEach(([k, v]) => {
if(!acc.has(k)) acc.set(k, [k])
acc.get(k).push(Array.isArray(v) ? v.join(' | ') : v)
})
return acc
}, new Map()).values())
console.log(result)
You could simply map the value and check if an item is an array, then take the joined values or the value itself.
const
data = [{ id: 1, name: "name1", price: 6.95, promoPrice: 5.91, category: ["test1, test2"] }, { id: 2, name: "name2", price: 998.95, promoPrice: 333.91, category: ["test3, test4"] }],
headers = ["id", "name", "price", "promoPrice", "category"],
result = data
.reduce(
(r, o) => headers.map((k, i) => [
...r[i],
Array.isArray(o[k]) ? o[k].join(' | ') : o[k]
]),
headers.map(k => [k]),
);
console.log(result);
.as-console-wrapper { max-height: 100% !important; top: 0; }
construct one init array with all possible keys with the wanted order, then uses Array.reduce and Array.forEach to Array.push value for per key based on its index.
const arrayObj = [
{
"id":1,
"name":"name1",
"price":6.95,
"promoPrice":5.91,
"category":["test1", "test2"]
},
{
"id":2,
"name":"name2",
"price":998.95,
"promoPrice":333.91,
"category":["test3", "test4"]
}
]
function ConvertToArray2D (items) {
let init = [['id'], ['name'], ['price'], ['promoPrice'], ['category']]
if (!items) return init
return arrayObj.reduce((pre, cur) => {
init.forEach((key, index) => {
pre[index].push(Array.isArray(cur[key[0]]) ? cur[key[0]].join('|') : cur[key[0]])
})
return pre
}, init.slice())
}
console.log(ConvertToArray2D(arrayObj))
This can be handled with a standard 'zip' after mapping your objects to arrays of values in line with the headers array. (This also allows for the result to be pivoted back).
//** #see https://stackoverflow.com/a/10284006/13762301
const zip = (...rs) => [...rs[0]].map((_, c) => rs.map((r) => r[c]));
const headers = ['id', 'name', 'price', 'promoPrice', 'category'];
const arrayObj = [{ id: 1, name: 'name1', price: 6.95, promoPrice: 5.91, category: ['test1', 'test2'] },{ id: 2, name: 'name2', price: 998.95, promoPrice: 333.91, category: ['test3', 'test4'] },];
const result = zip(
headers,
...arrayObj.map((o) => headers.map(h => Array.isArray(o[h]) ? o[h].join(' | ') : o[h]))
);
console.log(result);
// which also allows it to be reversed
console.log(zip(...result));
.as-console-wrapper { max-height: 100% !important; top: 0; }
see: Javascript equivalent of Python's zip function for further zip discussion.

Map Json data by JavaScript

I have a Json data that I want to have in a different format.
My original json data is:
{
"info": {
"file1": {
"book1": {
"lines": {
"102:0": [
"102:0"
],
"105:4": [
"106:4"
],
"106:4": [
"107:1",
"108:1"
]
}
}
}
}
}
And I want to map it as following:
{
"name": "main",
"children": [
{
"name": "file1",
"children": [
{
"name": "book1",
"group": "1",
"lines": [
"102",
"102"
],
[
"105",
"106"
],
[
"106",
"107",
"108"
]
}
],
"group": 1,
}
],
"group": 0
}
But the number of books and number of files will be more. Here in the lines the 1st part (before the :) inside the "" is taken ("106:4" becomes "106"). The number from the key goes 1st and then the number(s) from the value goes and make a list (["106", "107", "108"]). The group information is new and it depends on parent-child information. 1st parent is group 0 and so on. The first name ("main") is also user defined.
I tried the following code so far:
function build(data) {
return Object.entries(data).reduce((r, [key, value], idx) => {
//const obj = {}
const obj = {
name: 'main',
children: [],
group: 0,
lines: []
}
if (key !== 'reduced control flow') {
obj.name = key;
obj.children = build(value)
if(!(key.includes(":")))
obj.group = idx + 1;
} else {
if (!obj.lines) obj.lines = [];
Object.entries(value).forEach(([k, v]) => {
obj.lines.push([k, ...v].map(e => e.split(':').shift()))
})
}
r.push(obj)
return r;
}, [])
}
const result = build(data);
console.log(result);
The group information is not generating correctly. I am trying to figure out that how to get the correct group information. I would really appreciate if you can help me to figure it out.
You could use reduce method and create recursive function to build the nested structure.
const data = {"info":{"file1":{"book1":{"lines":{"102:0":["102:0"],"105:4":["106:4"],"106:4":["107:1","108:1"]}}}}}
function build(data) {
return Object.entries(data).reduce((r, [key, value]) => {
const obj = {}
if (key !== 'lines') {
obj.name = key;
obj.children = build(value)
} else {
if (!obj.lines) obj.lines = [];
Object.entries(value).forEach(([k, v]) => {
obj.lines.push([k, ...v].map(e => e.split(':').shift()))
})
}
r.push(obj)
return r;
}, [])
}
const result = build(data);
console.log(result);
I couldn't understand the logic behind group property, so you might need to add more info for that, but for the rest, you can try these 2 functions that recursively transform the object into what you are trying to get.
var a = {"info":{"file1":{"book1":{"lines":{"102:0":["102:0"],"105:4":["106:4"],"106:4":["107:1","108:1"]}}}}};
var transform = function (o) {
return Object.keys(o)
.map((k) => {
return {"name": k, "children": (k === "lines" ? parseLines(o[k]) : transform(o[k])) }
}
)
}
var parseLines = function (lines) {
return Object.keys(lines)
.map(v => [v.split(':')[0], ...(lines[v].map(l => l.split(":")[0]))])
}
console.log(JSON.stringify(transform(a)[0], null, 2));

How to separate the difference from an array object?

My existing array object are
//existing object
var existing = [
{
'ProviderCode':'aa',
'msg':'....',
},{
'ProviderCode':'bb',
'msg':'....',
},{
'ProviderCode':'cc',
'msg':'....',
},{
'ProviderCode':'dd',
'msg':'....',
},{
'ProviderCode':'ee',
'msg':'....',
}];
new object I'm comparing to
var new = [
{
'ProviderCode':'bb',
'msg':'....',
},{
'ProviderCode':'cc',
'msg':'....',
},{
'ProviderCode':'ee',
'msg':'....',
},{
'ProviderCode':'ff',
'msg':'....',
},{
'ProviderCode':'gg',
'msg':'....',
}];
I would like to generate same, remove and add array based on the two array objects, I can get the same array object but not the remove and add object from the objects.
var same = []; //bb, cc, ee //these will be the match
var remove = []; //aa , dd //will be remove from existing
var add = []; //ff, gg //will be consider as add
//I can get the same using below:
e.forEach(function(ev,ei,ea){
n.forEach(function(nv,ni,na){
if( ev.ProviderCode === nv.ProviderCode ){
s.push({ProviderCode:ev.ProviderCode,msg:"Same, do nothing"});
}
});
});
/* //output:
[{
"ProviderCode": "bb",
"msg": "Same, do nothing"
}, {
"ProviderCode": "cc",
"msg": "Same, do nothing"
}, {
"ProviderCode": "ee",
"msg": "Same, do nothing"
}]
*/
//but how do I get remove and add array object?
//remove will be:
/* //output:
[{
"ProviderCode": "aa",
"msg": "removed"
}, {
"ProviderCode": "dd",
"msg": "removed"
}]
*/
//add will be:
/* //output:
[{
"ProviderCode": "ff",
"msg": "added"
}, {
"ProviderCode": "gg",
"msg": "added"
}]
*/
You can use Array.prototype.filter & Array.prototype.find for this:
let existing = [{ProviderCode:'aa'},{ProviderCode:'bb'},{ProviderCode:'cc'},{ProviderCode:'dd'},{ProviderCode:'ee'}];
let newData = [{ProviderCode:'bb'},{ProviderCode:'cc'},{ProviderCode:'ee'},{ProviderCode:'ff'},{ProviderCode:'gg'}];
let added = newData.filter(d => !existing.find(e => d.ProviderCode === e.ProviderCode));
console.log("ADDED:", added);
let removed = existing.filter(d => !newData.find(e => d.ProviderCode === e.ProviderCode));
console.log("REMOVED:", added);
let same = newData.filter(d => existing.find(e => d.ProviderCode === e.ProviderCode));
console.log("SAME:", same);
With a library like lodash this is a bit easier:
let existing = [{ProviderCode:'aa'},{ProviderCode:'bb'},{ProviderCode:'cc'},{ProviderCode:'dd'},{ProviderCode:'ee'}];
let newData = [{ProviderCode:'bb'},{ProviderCode:'cc'},{ProviderCode:'ee'},{ProviderCode:'ff'},{ProviderCode:'gg'}];
console.log("ADDED:" , _.differenceBy(newData, existing, 'ProviderCode'));
console.log("REMOVED:", _.differenceBy(existing, newData, 'ProviderCode'));
console.log("SAME:" , _.intersectionBy(newData, existing, 'ProviderCode'));
<script src="https://unpkg.com/lodash#4.17.15/lodash.min.js"></script>
You can use this little "library" that provides set operations for JS Map objects:
function mapUnion(m1, m2) {
let m = new Map();
for (let [k, v] of m1)
m.set(k, v);
for (let [k, v] of m2)
m.set(k, v);
return m;
}
function mapIntersection(m1, m2) {
let m = new Map();
for (let [k, v] of m1)
if (m2.has(k))
m.set(k, v);
return m;
}
function mapDifference(m1, m2) {
let m = new Map();
for (let [k, v] of m1)
if (!m2.has(k))
m.set(k, v);
return m;
}
Having this, you can convert both your arrays to Maps:
let m1 = new Map(oldArray.map(x => [x.ProviderCode, x]))
let m2 = new Map(newArray.map(x => [x.ProviderCode, x]))
and do whatever you want with these, for example,
console.log(mapIntersection(m1, m2)) // bb=>..., cc=>..., ee=>...
console.log(mapDifference(m1, m2)) // aa=>..., dd=>...
If you need arrays as results:
commonObjects = Array.from(mapIntersection(m1, m2).values())
You could take some sets and get the wanted items for each change.
const
providerCode = ({ ProviderCode }) => ProviderCode;
var existingData = [{ ProviderCode: 'aa' }, { ProviderCode: 'bb' }, { ProviderCode: 'cc' }, { ProviderCode:'dd' }, { ProviderCode: 'ee' }],
newData = [{ ProviderCode: 'bb' }, { ProviderCode: 'cc' }, { ProviderCode: 'ee' }, { ProviderCode: 'ff' }, { ProviderCode: 'gg' }],
existingSet = new Set(existingData.map(providerCode)),
newSet = new Set(newData.map(providerCode)),
same = [...existingSet].filter(Set.prototype.has, newSet),
add = [...newSet].filter(v => !existingSet.has(v)),
remove = [...existingSet].filter(v => !newSet.has(v));
console.log(...same);
console.log(...add);
console.log(...remove);

Destructuring array of objects in es6

In es6, how can i simplify the following lines using destructuring?:
const array0 = someArray[0].data;
const array1 = someArray[1].data;
const array2 = someArray[2].data;
Whether using destructuring would actually be a simplification is debatable but this is how it can be done:
const [
{ data: array0 },
{ data: array1 },
{ data: array2 }
] = someArray
Live Example:
const someArray = [
{ data: 1 },
{ data: 2 },
{ data: 3 }
];
const [
{ data: array0 },
{ data: array1 },
{ data: array2 }
] = someArray
console.log(array0, array1, array2);
What is happening is that you're first extracting each object from someArray then destructuring each object by extracting the data property and renaming it:
// these 2 destructuring steps
const [ obj1, obj2, obj3 ] = someArray // step 1
const { data: array0 } = obj1 // step 2
const { data: array1 } = obj2 // step 2
const { data: array2 } = obj3 // step 2
// written together give
const [
{ data: array0 },
{ data: array1 },
{ data: array2 }
] = someArray
Maybe combine destructuring with mapping for (potentially) more readable code:
const [array0, array1, array2] = someArray.map(item => item.data)
Live Example:
const someArray = [
{ data: 1 },
{ data: 2 },
{ data: 3 }
];
const [array0, array1, array2] = someArray.map(item => item.data)
console.log(array0, array1, array2);
I believe what you actually want is
const array = someArray.map(x => x.data)
If you really want three variables (Hint: you shouldn't), you can combine that mapping with destructuring:
const [array0, array1, array2] = someArray.map(x => x.data)
If you want to do with this pure JS then follow this code snippet. It will help you.
let myArray = [
{
"_id": "1",
"subdata": [
{
"subid": "11",
"name": "A"
},
{
"subid": "12",
"name": "B"
}
]
},
{
"_id": "2",
"subdata": [
{
"subid": "12",
"name": "B"
},
{
"subid": "33",
"name": "E"
}
]
}
]
const array = myArray.map(x => x.subdata).flat(1)
const isExist = (key,value, a) => {
return a.find(item => item[key] == value)
}
let a = array.reduce((acc, curr) => {
if(!isExist('subid', curr.subid, acc)) {
acc.push(curr)
}
return acc
}, [])
console.log(a)
const myInfo = someArray.map((item) => {
const {itemval1, itemval2} = item;
return(
//return data how you want it eg:
<p>{itemval1}</p>
<p>{itemval2}</p>)
})
This is how I did it in react, correct me if m wrong, I'm still new to this world
#Daniel, I presume you were looking to destructure a nested Object in an array of Objects. Following #nem035 was able to extract the nested Object's property using his pattern.
What is happening is that you're first extracting each object from addresses array then destructuring each object by extracting its properties and renaming it including the nested Object:
addresses = [
{
locality:"Sarjapura, Bangalore",
coordinates:{latitude:"12.901160", longitude:"77.711680"}
},
{
locality:"Vadakara, Kozhikode",
coordinates:{latitude:"11.588980", longitude:"75.596450"}
}
]
const [
{locality:loc1, coordinates:{latitude:lat1, longitude:ltd1}},
{locality:loc2, coordinates:{latitude:lat2, longitude:ltd2}}
] = addresses
console.log(`Latitude of Vadakara :: ${lat2}`)

Categories