Javascript array format

Question

I have two javascript array

let a=[{id:1},{id:2},{id:3}];
let b=[{count:35, name:'test', age:12}, {count:45 name:'test2', age:9}];

and two array push into i need final Array format is

[{count:35,name:'test', age,12, id:1} , {count:35, name:'test', age:12,id:2},{count:35, name:'test', age:12,id:3},{count:45,name:'test', age,9, id:1} , {count:45, name:'test', age:9,id:2},{count:45, name:'test', age:9,id:3} ]

And i trying

for ( var index=0; index<b.length; index++ ) {
 
 for ( var j=0; j<a.length; j++ ) {
 for (const [key, value] of Object.entries(a[j])) {
 //if(j==index)
 b[index][key]=value;
 k[j]=b[index];
 }
 console.log( b[index]);
 c.push(b[index]);
 
 }
}
console.log(c);

and it shows final value is enter image description here

please any body help to fix the problem

• Open AI - Opting Out: I hope that clears things up.

Answer 1

Your current implementation, is essentially updating the same b objects over and over, x number of times, changing their IDs each time through, ending at 3.

You need to "clone" the objects, so they are separate objects, like so:

 let p = []; // Permutations
 
 let a = [{id:1},{id:2}]; // Renditions...
 // Presets...
 let b = [{count:35, name:'test', age:12}, {count:45, name:'test2', age:9}];
 
 // for each Rendition
 a.forEach(function(a) {
 // for each Preset
 b.forEach(function(b){
 // generate Permutation and Clone, object of b with additional id prop
 p.push(Object.assign({id: a.id}, b)); // <-- Cloned here...
 });
 });
 console.log(p)

for the sake of clarity, you might consider changing the id prop to grouping or group or group_id.

Answer 2

You could use flatMap:

let a=[{id:1},{id:2},{id:3}];
let b=[{count:35, name:'test', age:12}, {count:45, name:'test2', age:9}];
let m = b.flatMap(itemB => a.map(itemA => ({...itemB, ...itemA })))
console.log(m);

Answer 3

I got your problem. The thing is that you are mutating the same b object every iteration, that's why in the end you get id = 3 for every element. You can use a deep copy of b in each cycle, and the error should be gone.

Here's one way to deep clone, not the most efficient but it is very clear:

 const bCopy = JSON.parse(JSON.stringify(b[index]));
 for (const [key, value] of Object.entries(a[j])) {
 //if(j==index)
 bCopy[key]=value;
 k[j]=bCopy; // what's this for?
 }
 console.log(bCopy);
 c.push(bCopy);

Answer 4

Reduce b and for each item b1, reduce a. When reducing a, just assign both b1 and a1 to a new object.

const expectedValue = JSON.stringify(JSON.parse(
 document.getElementById('expected').value))
let a = [
 { id: 1 },
 { id: 2 },
 { id: 3 }
]
let b = [
 { count: 35, name: 'test', age: 12 },
 { count: 45, name: 'test2', age: 9 }
]
let c = b.reduce((res, b1) =>
 a.reduce((res1, a1) =>
 [...res1, Object.assign({}, b1, a1)], res), [])
console.log(JSON.stringify(c) === expectedValue)

.as-console-wrapper { top: 0; max-height: 100% !important; }
#expected { display: none; }

<textarea id="expected">
[
 { "count": 35, "name": "test", "age": 12, "id": 1 },
 { "count": 35, "name": "test", "age": 12, "id": 2 },
 { "count": 35, "name": "test", "age": 12, "id": 3 },
 { "count": 45, "name": "test2", "age": 9, "id": 1 },
 { "count": 45, "name": "test2", "age": 9, "id": 2 },
 { "count": 45, "name": "test2", "age": 9, "id": 3 }
]
</textarea>

Answer 5

Try this changes.

 let a=[{id:1},{id:2},{id:3}];
 let b=[{count:35, name:'test', age:12}, {count:45, name:'test2', age:9}];
 let c=[];
 for ( var index=0; index<b.length; index++ ) {
 for ( var j=0; j<a.length; j++ ) {
 var obj=b[index];
 for (const [key, value] of Object.entries(a[j])) {
 obj[key]=value;
 }
 c.push(obj);
 }
 }
 console.log(c);