Combine Array(s) into single object in JavaScript

Question

Currently I have 3 arrays:

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

I would like to merge all the array into one object instead and I tried using for loop but got an error instead:

var finalObj = {};

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

}

The end result I want to achieve:

finalObj = [{id:13, date:20181920, content:"content1"},
          {id:24, date:20181120, content:"content2"},
          {id:35, date:20172505, content:"content3"}];

Answer 1

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)

Answer 2

Your finalObj is an array of objects, so you must initialise it as an array, like this :

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

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

for the "pushing to final array" part, your code inside the loop may work if you add an extra finalObj[y] = {} to initialise it and so you have :

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

an it works but

  finalObj.push(
    { id: idArray[y], date: dateArray[y], content : contentArray[y] }
  )

is shorter and still readable i think :)