Push object in Javascript

Question

I need to push object to array in Javascript, but every time push overwrite the same object I have had already added. For example:

//This is object list
var NewIssue = {};
//This is array
var newIssueList = [];
function myFunction() {
 for (var i = 0; i < 3; i++) {
 NewIssue.Id = i;
 NewIssue.Number = 233 + i;
 NewIssue.Name = "Test" + i.toString();
 newIssueList.push(NewIssue);
 }
}

In the end I will have newIssueList with 3 same objects. Why it does overwrite the first and how to solve this problem?

• Pointy: Add NewIssue = {}; to the top of the loop.
• Heretic Monkey: Possible duplicate of Push is overwriting previous data in array

Answer 1

You have to move the object inside the loop.

var newIssueList = [];
function myFunction() {
 for (var i = 0; i < 3; i++) {
 var NewIssue = {};
 NewIssue.Id = i;
 NewIssue.Number = 233 + i;
 NewIssue.Name = "Test" + i.toString();
 newIssueList.push(NewIssue);
 }
}
myFunction();
console.log(newIssueList);

And then you could just extend the object literal a but to make it much more readable:

 for (var i = 0; i < 3; i++) {
 var NewIssue = {
 Id:i,
 Number:233+i,
 Name:"Test"+i
 };
 newIssueList.push(NewIssue);
 }

Answer 2

You can also avoid using a superfluous var by creating an inline object:

newIssueList.push({
 Id: i,
 Number: 233 + i,
 Name: "Test" + i.toString()
});

Answer 3

There is only one object, and each time you push it into the array, you push a reference to the existing object. When you change the object, every element in the array reflects this, as they all point to the same object.

You need to create a new object on every iteration.

//This is array
var newIssueList = [];
function myFunction() {
 for (var i = 0; i < 3; i++) {
 newIssueList.push({
 id: i,
 number: 233 + i,
 name: "Test" + i.toString()
 });
 }
}
myFunction();
console.log(newIssueList);