append value to javascript array

Question

If one want to append to this type of array:

array = ["one","two","three"];

so it becomes,

array = ["one","two","three, "four"];

use:

array.push("four");

but how do you append here:

object = {element1: one, element2: two, array: ["one","two","three"]};

so it becomes,

object = {element1: one, element2: two, array: ["one","two","three,"four"]};

Answer 1

You still use push(), but on the array property of your object:

var obj = {
 element1: 1,
 element2: 2,
 array: ["one", "two", "three"]
};
obj.array.push('four');
console.log(obj);

• haz: supposing instead of var obj we have jQuery.obj ?
• Rory McCrossan: What do you mean by jQuery.obj?
• haz: jQuery.obj = { element1: 1, ... }
• Rory McCrossan: Then use jQuery.obj.array.push('four'); However you really, really should not be polluting the jQuery namespace with your own variables.
• haz: I did. I then get error: Reference Error: Cant find variable array

Answer 2

You can update an object in place like so:

let obj = {element1: 'one', element2: 'two', array: ["one","two","three"]};
obj.array.push('four');

If you want to create a new copy of the object with the extended array, you can also do the following using the new ES6 features:

let obj = {element1: 'one', element2: 'two', array: ["one","two","three"]};
let newObject = Object.assign({}, obj, { array: [...obj.array, 'four'] });

Using the second example, you keep the original object intact and create a new copy with the updated values.

Answer 3

In your case the values one, two have to be strings, otherwise they will be treated as variables, and you can use push too for the object using object.array.push('four');:

var object = {
 element1: "one",
 element2: "two",
 array: ["one", "two", "three"]
};
object.array.push('four');
console.log(object);