Combine Array(s) into single object in JavaScript

finalObj is an object you need to push the value in an array.Beside you can also use array map method which will return an array so there is no need to separately push the values to an array.

Use map method on any of the arrays and use the index to get the corresponding values from other array

var idArray = [13, 24, 35];
var dateArray = [20181920, 20181120, 20172505];
var contentArray = ["content1", "content2", "content3"];

let m = idArray.map(function(item, index) {
  // here the map method will push the object to an 
  // array and will return that array
  return {
    id: item,
    date: dateArray[index],
    content: contentArray[index]
  }

})
console.log(m)

let newObjArray = idArray.map((value, index) => {
        return {
            id: value,
            date: dateArray[index],
            content:contentArray[index]
        }

    });
console.log(newObjArray);

Well, I'm assuming you want an Array Of Objects which has the same length with the idArrays and others.

Here's some code for that:

var finalObjArray = [];

for (var y = 0; y < dateArray.length; y++) { 
    finalObjArray.push({
                       id: idArray[y],
                       date: dateArrayArrange[y],
                       content: contentArray[y]
    });

}

Basically you are adding objects to that array. Hope it helps :)

There isn’t a record of finalObj[y] when you set properties, so it return undefined instead.

To fix your problem, create a object with properties then push it to your array.

You can do it like this:

    var idArray = [13, 24, 35];    
    var dateArray = [20181920, 20181120, 20172505];
    var contentArray = ["content1", "content2", "content3"];
    
    var final = [];
    
    for (let y = 0; y < idArray.length; y++) { 
    	let tmp = {};
        tmp.id = idArray[y];
        tmp.date =  dateArray[y];
        tmp.content =  contentArray[y];
        
        final.push(tmp);
    
    }
    
    console.log(final)

Note: dateArrayArrange does not even exist, I think you mean just dateArray

You need to create objects and add them to the array. This code should work.

var idArray = [13, 24, 35];    
var dateArray = [20181920, 20181120, 20172505];
var contentArray = ["content1", "content2", "content3"];
var finalObj = [];

for (var y = 0; y < dateArray.length; y++) { 
    object = {};
    object.id = idArray[y];
    object.date =  dateArray[y];
    object.content =  contentArray[y];
    finalObj[y] = object;
}

You could collect all key value pairs (for an arbitrary count) in an object and reduce the object while mapping the values.

var id = [13, 24, 35],
    date = [20181920, 20181120, 20172505],
    content = ["content1", "content2", "content3"],
    result = Object
        .entries({ id, date, content })
        .reduce((r, [k, values]) => values.map((v, i) => ({ ...r[i], [k]: v })), []);
        
console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

by using maps we can write a function which we can extend to any number of arrays and so on. the below function takes a minimum of three distinct fields.

function joinArrays(id, date, content,...array){
    const Arr = [...array];
    const newArr = new Array(Arr.length)
    for(let i=0; i<newArr.length;i++){
        newArr[i] ={}
    }
    Arr.map((rowArr,index)=>{
        rowArr.map((i,k)=>
            {
                key = arguments[index];
                let obj = {};
                obj[key] = i;
                newArr[k]=Object.assign(newArr[k],obj)}
        )
    }
    )
    console.log(newArr);
    return newArr;

}
target = joinArrays('id', 'date', 'content',idArray,dateArray,contentArray);