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How to merge two arrays to make an object [duplicate]

This question already has answers here:
Create an object from an array of keys and an array of values
(9 answers)
Closed 1 year ago.
consider i have an array say
let arr1=["john","Bruce","Clent"];
and
let arr2=[55,33,22];
Then how can i make an object out of this in javascript
object should look like:{"john":55,"Bruce":33,"Clent":22};
it should take arr1 as object's keys and arr2 as object'values

You can just loop the array, but use the index to match the key and value.
const arr1=["john","Bruce","Clent"];
const arr2=[55,33,22];
const obj = {};
arr1.forEach((val, i) => {
obj[val] = arr2[i];
});

How to extract values of individual objects from an array of objects [duplicate]

This question already has answers here:
Convert JavaScript array of 2 element arrays into object key value pairs
(5 answers)
Closed 3 years ago.
I have an array of objects like this
const jsonx =[{"name":"John Doe"},{"name2":"Marry Doe"},{"name3":"Michael"}]
What I am trying to achieve are the values of each object out of the array as follows
{"name":"John Doe","name2":"Marry Doe","name3":"Michael"}
I have tried the following methods, but did not manage to get what I need.
//console.log(Array.of(...jsonx));
//console.log(JSON.stringify(jsonx));

Alternatively, you can make use of ES6's spread syntax and Object.assign. (My favourite way of doing things)
const jsonx =[{"name":"John Doe"},{"name2":"Marry Doe"},{"name3":"Michael"}];
const res = Object.assign({}, ...jsonx);
console.log(res);

You can try with Array.prototype.reduce()
The reduce() method executes a reducer function (that you provide) on each member of the array resulting in a single output value.
and Object.assign()
The Object.assign() method is used to copy the values of all enumerable own properties from one or more source objects to a target object. It will return the target object.
const jsonx =[{"name":"John Doe"},{"name2":"Marry Doe"},{"name3":"Michael"}];
var res = jsonx.reduce((a, c) => Object.assign(a, c), {});
console.log(res);

You can use reduce for it:
const jsonx =[{"name":"John Doe"},{"name2":"Marry Doe"},{"name3":"Michael"}]
const res = jsonx.reduce((acc,curr) => ({...acc, ...curr}), {});
console.log(res)

You can use flatMap() and reduce()
const jsonx =[{"name":"John Doe"},{"name2":"Marry Doe"},{"name3":"Michael"}]
let res = jsonx.flatMap(x => Object.entries(x)).reduce((ac,[k,v]) => ({...ac,[k]:v}),{})
console.log(res)

You can also try
jsonx.reduce((r, a) => Object.assign(r, a))
OR
Object.assign({}, ...jsonx)

Convert array to object keys [duplicate]

This question already has answers here:
Return object with default values from array in Javascript
(4 answers)
How to convert an Object {} to an Array [] of key-value pairs in JavaScript
(21 answers)
Closed 4 years ago.
What's the best way to convert an array, to an object with those array values as keys, empty strings serve as the values of the new object.
['a','b','c']
to:
{
a: '',
b: '',
c: ''
}

try with Array#Reduce
const arr = ['a','b','c'];
const res = arr.reduce((acc,curr)=> (acc[curr]='',acc),{});
console.log(res)

You can use Array.prototype.reduce()and Computed property names
let arr = ['a','b','c'];
let obj = arr.reduce((ac,a) => ({...ac,[a]:''}),{});
console.log(obj);

const target = {}; ['a','b','c'].forEach(key => target[key] = "");

You can use Object.assign property to combine objects created with a map function, please take into account that if values of array elements are not unique the latter ones will overwrite previous ones
const array = Object.assign({},...["a","b","c"].map(key => ({[key]: ""})));
console.log(array);

You can use array reduce function & pass an empty object in the accumulator. In this accumulator add key which is denoted by curr
let k = ['a', 'b', 'c']
let obj = k.reduce(function(acc, curr) {
acc[curr] = '';
return acc;
}, {});
console.log(obj)

Merge multiple arrays in object [duplicate]

This question already has answers here:
Concatenate Object values
(4 answers)
Closed 7 months ago.
I'm looking at an efficient way to merge multiple array props in an object.
The object, can have multiple array properties in there :
{
"col0Codes": [
"ABC",
"XYZ",
"UYA",
"ZZA",
"AAW",
"MYP"
],
"col1Codes": [
"CNA",
"ZYA",
"OIA",
"POQ",
"LMO",
"OPI"
],
"col2Codes": [
"CNA",
"ZYA",
"OIA",
"POQ",
"LMO",
"OPI"
],
"col3Codes": [
"..."
],
"col4Codes": [
"..."
],
...
}
Result: All the codes in a single array
["ABC","XYZ","UYA","ZZA","AAW","MYP","CNA","ZYA","OIA","POQ","LMO","OPI",....]
I've tried using concat but this creates a new array every single time and overwrites the previous one, I feel this is not fast and memory efficient.
let colCodes = []
for (let i in data) {
colCodes = colCodes .concat(i)
}
console.log(activityCodes)
I've tried using push, but for some reason it does not merge all the entries into one single array but creates a single array with number of props in the object as shown below
let colCodes = []
for (let i in data) {
colCodes.push(i)
}
console.log(colCodes)
[Array(6), Array(5), ....]
Is there anyway I can achieve this using reduce, if that is what'll be fast and mem efficient ?

You can get an array of arrays using Object.values(), and then flatten them to a single array using Array.flat():
const data = {"col0Codes":["ABC","XYZ","UYA","ZZA","AAW","MYP"],"col1Codes":["CNA","ZYA","OIA","POQ","LMO","OPI"],"col2Codes":["CNA","ZYA","OIA","POQ","LMO","OPI"]};
const result = Object.values(data).flat();
console.log(result);
Old answer:
You can get the Object.values(), then merge by spreading into Array.concat():
const data = {"col0Codes":["ABC","XYZ","UYA","ZZA","AAW","MYP"],"col1Codes":["CNA","ZYA","OIA","POQ","LMO","OPI"],"col2Codes":["CNA","ZYA","OIA","POQ","LMO","OPI"]};
const result = [].concat(...Object.values(data));
console.log(result);

You could also simply Array.reduce the Object.values with ES6 spread:
const input={"col0Codes":["ABC","XYZ","UYA","ZZA","AAW","MYP"],"col1Codes":["CNA","ZYA","OIA","POQ","LMO","OPI"],"col2Codes":["CNA","ZYA","OIA","POQ","LMO","OPI"]};
console.log(Object.values(input).reduce((r,c) => [...r, ...c]))

One way would be to use Array.prototype.flat, and call it on the values of the object:
const input={"col0Codes":["ABC","XYZ","UYA","ZZA","AAW","MYP"],"col1Codes":["CNA","ZYA","OIA","POQ","LMO","OPI"],"col2Codes":["CNA","ZYA","OIA","POQ","LMO","OPI"]};
console.log(
Object.values(input).flat()
);

You can try this
let obj = {"col0Codes": ["ABC","XYZ","UYA","ZZA","AAW","MYP"],
"col1Codes": ["CNA","ZYA","OIA","POQ","LMO","OPI"],
"col2Codes": ["CNA","ZYA","OIA","POQ","LMO","OPI"],
"col3Codes": ["..."],
"col4Codes": ["..."]
}
let op = [];
for(let key in obj){
op.push(...obj[key])
}
console.log(op)

JS: Convert An Array Into An Object Without Indexes [duplicate]

This question already has answers here:
Return object with default values from array in Javascript
(4 answers)
How to convert an Object {} to an Array [] of key-value pairs in JavaScript
(21 answers)
Closed 4 years ago.
What's the best way to convert an array, to an object with those array values as keys, empty strings serve as the values of the new object.
['a','b','c']
to:
{
a: '',
b: '',
c: ''
}

try with Array#Reduce
const arr = ['a','b','c'];
const res = arr.reduce((acc,curr)=> (acc[curr]='',acc),{});
console.log(res)

You can use Array.prototype.reduce()and Computed property names
let arr = ['a','b','c'];
let obj = arr.reduce((ac,a) => ({...ac,[a]:''}),{});
console.log(obj);

const target = {}; ['a','b','c'].forEach(key => target[key] = "");

You can use Object.assign property to combine objects created with a map function, please take into account that if values of array elements are not unique the latter ones will overwrite previous ones
const array = Object.assign({},...["a","b","c"].map(key => ({[key]: ""})));
console.log(array);

You can use array reduce function & pass an empty object in the accumulator. In this accumulator add key which is denoted by curr
let k = ['a', 'b', 'c']
let obj = k.reduce(function(acc, curr) {
acc[curr] = '';
return acc;
}, {});
console.log(obj)