How to turn an object with keys as indexes into an array in JavaScript? [duplicate]

Question

I want to convert an object with indexes as keys, into an array in JavaScript.

For example:

Input: obj ={1: 'banana', 2: 'apple',3:'orange' }

Output: ['orange','apple','banana' ]

I have tried with 'Array.prototype.reverse.apply(obj)', but not able to get the result.

 var obj ={1: 'banana', 2: 'apple',3:'orange' };
 var res =Array.prototype.reverse.apply(obj);
 console.log(res); // return the same object, not reverse

What are the other usages of Array.prototype.reverse()?

Answer 1

You can first convert your almost-array-like object to a real array, and then use .reverse():

Object.assign([], {1:'banana', 2:'apple', 3:'orange'}).reverse();
// [ "orange", "apple", "banana", <1 empty slot> ]

The empty slot at the end if cause because your first index is 1 instead of 0. You can remove the empty slot with .length-- or .pop().

Alternatively, if you want to borrow .reverse and call it on the same object, it must be a fully-array-like object. That is, it needs a length property:

Array.prototype.reverse.call({1:'banana', 2:'apple', 3:'orange', length:4});
// {0:"orange", 1:"apple", 3:"banana", length:4}

Note it will return the same fully-array-like object object, so it won't be a real array. You can then use delete to remove the length property.