CODEWITHSUNDEEP
javascriptobject
sprugman
sprugman

Reputation: 19831

How can I get the last item in a JavaScript object?

If I have an object like: 

{ 'a' : 'apple', 'b' : 'banana', 'c' : 'carrot' }

If I don't know in advance that the list goes up to 'c', other than looping through the object, is there a way to get the last item in the object (e.g. 'carrot')?

Upvotes: 129

Views: 222861

Answers (16)

Ehsanullah Qadeer
Ehsanullah Qadeer

Reputation: 1

 const obj = { a: 'apple', b: 'banana', c: 'carrot' };
    
    // Get the last value using slice
    const values = Object.values(obj);
    const lastValue = values.slice(-1)[0];
    
    console.log(`Last value: ${lastValue}`);
    // Last value: carrot

Upvotes: 0

somebodysomewhere
somebodysomewhere

Reputation: 1146

The other answers overcomplicate it for me.

let animals = {
  a: 'dog',
  b: 'cat',
  c: 'bird'
}

let lastKey = Object.keys(animals).pop()
let lastValue = animals[Object.keys(animals).pop()]

Upvotes: 21

grehh
grehh

Reputation: 31

const fruitObject = { 'a' : 'apple', 'b' : 'banana', 'c' : 'carrot' };
const lastValue = Object.values(fruitObject).slice(-1)[0];

It seems to be a short way.

https://developer.mozilla.org/de/docs/Web/JavaScript/Reference/Global_Objects/Object/values https://developer.mozilla.org/de/docs/Web/JavaScript/Reference/Global_Objects/Array/slice

Upvotes: 3

AshNaz87
AshNaz87

Reputation: 434

You could also use the Object.values() method:

Object.values(fruitObject)[Object.values(fruitObject).length - 1]; // "carrot"

Edit

To improve performance, you could create a variable:

const fruitValues = Object.values(fruitObject);

To give you:

fruitValues[fruitValues.length - 1];

Upvotes: 3

meder omuraliev
meder omuraliev

Reputation: 186562

Use an array, not an object literal, if order matters.

const list = ['apple', 'banana', 'carrot'];

Or something like

const dict = {
 'a' : ['apple', 'awesome'],
 'b' : ['best friend']
};

Or even..

const dict = [{letter:'a', list:['apple', 'awesome']},
              {letter:'b', list:['best friend']}];

The keys for dict are not guaranteed at all to be in order.

Upvotes: 5

Shapon Pal
Shapon Pal

Reputation: 1146

You can try this. This will store last item. Here need to convert obj into array. Then use array pop() function that will return last item from converted array.

var obj = { 'a' : 'apple', 'b' : 'banana', 'c' : 'carrot' };
var last = Object.keys(obj).pop();
console.log(last);
console.log(obj[last]);

Upvotes: 8

Kristina Stefanova
Kristina Stefanova

Reputation: 2845

Yes, there is a way using Object.keys(obj). It is explained in this page:

var fruitObject = { 'a' : 'apple', 'b' : 'banana', 'c' : 'carrot' };
Object.keys(fruitObject); // this returns all properties in an array ["a", "b", "c"]

If you want to get the value of the last object, you could do this:

fruitObject[Object.keys(fruitObject)[Object.keys(fruitObject).length - 1]] // "carrot"

Upvotes: 282

Raphael PICCOLO
Raphael PICCOLO

Reputation: 2175

if you mean get the last key alphabetically, you can (garanteed) :

var obj = { 'a' : 'apple', 'b' : 'banana', 'c' : 'carrot' };
var keys = Object.keys(obj);
keys.sort();
var lastkey = keys.pop() // c
var lastvalue = obj[lastkey] // 'carrot'

Upvotes: 0

diogo
diogo

Reputation: 771

Let obj be your object. Exec:

(_ => _[Object.keys(_).pop()])( obj )

Upvotes: 0

user3282891
user3282891

Reputation: 317

last = Object.keys(obj)[Object.keys(obj).length-1];

where obj is your object

Upvotes: 30

ollazarev
ollazarev

Reputation: 1096

Solution using the destructuring assignment syntax of ES6:

var temp = { 'a' : 'apple', 'b' : 'banana', 'c' : 'carrot' };
var { [Object.keys(temp).pop()]: lastItem } = temp;
console.info(lastItem); //"carrot"

Upvotes: 11

Reha Ozenc
Reha Ozenc

Reputation: 39

JSArray = { 'a' : 'apple', 'b' : 'banana', 'c' : 'carrot' };  
document.write(Object.keys(JSArray)[Object.keys(JSArray).length-1]);// writes 'c'   
document.write(JSArray[Object.keys(JSArray)[Object.keys(JSArray).length-1]]); // writes 'carrot'

Upvotes: 3

vatsa
vatsa

Reputation: 134

Map object in JavaScript . This is already about 3 years old now. This map data structure retains the order in which items are inserted. With this retrieving last item will actually result in latest item inserted in the Map

Upvotes: 0

George
George

Reputation: 159

var myObj = {a: 1, b: 2, c: 3}, lastProperty;
for (lastProperty in myObj);
lastProperty;
//"c";

source:http://javascriptweblog.wordpress.com

Upvotes: 15

MooGoo
MooGoo

Reputation: 48240

As for the ordering of object properties in Javascript, I will just link to this answer:

Elements order in a "for (… in …)" loop

Specifically:

All modern implementations of ECMAScript iterate through object properties in the order in which they were defined

So every other answer here is correct, there is no official guaranteed order to object properties. However in practice there is (barring any bugs which naturally can screw up even set-in-stone officially specified behavior).

Furthermore, the de-facto enumeration order of object properties is likely to be codified in future EMCAScript specs.

Still, at this time I would not write code around this, mostly because there are no built-in tools to help deal with object property order. You could write your own, but in the end you'd always be looping over each property in an object to determine its position.

As such the answer to your question is No, there is no way besides looping through an object.

Upvotes: 5

Alex
Alex

Reputation: 65942

No. Order is not guaranteed in JSON and most other key-value data structures, so therefore the last item could sometimes be carrot and at other times be banana and so on. If you need to rely on ordering, your best bet is to go with arrays. The power of key-value data structures lies in accessing values by their keys, not in being able to get the nth item of the object.

Upvotes: 79

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