JavaScript Remove Object From Array & Return It

Question

Using JavaScript how can I remove an object from an array and return that object? For example, change this:

[{first:"John", last:"Smith"}]

...to this:

{first:"John", last:"Smith"}

http://plnkr.co/edit/VqBCsXGuMM54MwHIKW3c?p=preview

• jfriend00: You will have to show a little more context of the variable construction for a complete answer. Is this array assigned to a variable by itself or part of some other object?
• Ryan: @jfriend00 It's assigned to a variable by itself - Plunker added.

Answer 1

Use splice. It will remove some items from the array and return them.

var data = [{first:"John", last:"Smith"}];
var extract = data.splice(0, 1);
console.log(extract, data); // will print: {first..., last...}, []

Note that splice does return an array itself, so you'll have to take the appropriate elements from that.

If you only have a single element, you can splice, pop, or simply take the element by index and then truncate the array.

• Ryan: .splice is returning an array with an object (not just an object). Am I missing something? Compare to myObject: plnkr.co/edit/Pg3rLv2Lspj118i34EBa?p=preview
• ssube: @Ryan I mentioned that in the answer. splice will remove the elements from the original array and return a new array, which you have to take the element from normally (data.splice(0, 1)[0] or the like). It does the important step of removing, especially since it can remove element(s) from the middle of another array efficiently.
• Ryan: So that's my question, how can I return just an object (not an array with an object)? I'm getting undefined when I try .pop(): plnkr.co/edit/Pg3rLv2Lspj118i34EBa?p=preview
• ssube: You can use data.splice(0, 1).pop() or data.splice(0, 1)[0] or any number of other methods. There is no built-in method (that I know of) to splice a single element out of an array and return it as an object, probably because that behavior wouldn't make sense for multiple elements.
• Ryan: data.splice(0, 1).pop(); and data.splice(0, 1)[0] both return undefined plnkr.co/edit/Pg3rLv2Lspj118i34EBa?p=preview

Answer 2

You could use the pop() method. It will always remove the last element from array and handle it to you;

Example:

var myArray = [{first:"John", last:"Smith"}]
var myObject = myArray.pop()

Now your myObject value will be {first:"John", last:"Smith"} and your myArray will be empty

If you had more than one items:

var myArray = [{first:"John", last:"Smith"}, {first:"Test", last:"Now"}]
var myObject = myArray.pop()

What happens here is that your myArray will have just the first value and the myObject will have the last one {first:"Test", last:"Now"}

You could also take a look at splice()