JavascriptHow-ToBeginner · 3 min read

How to Sort Object by Key in JavaScript: Simple Guide

To sort an object by its keys in JavaScript, first get the keys using Object.keys(), then sort them with Array.prototype.sort(), and finally create a new object with keys in sorted order. This approach keeps the original object unchanged and returns a new sorted object.

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Syntax

Use Object.keys(obj) to get all keys, then sort them with keys.sort(). Create a new object by iterating over sorted keys and assigning values from the original object.

This process does not change the original object but returns a new one with keys in sorted order.

javascript

const sortedObj = Object.keys(obj)
  .sort()
  .reduce((acc, key) => {
    acc[key] = obj[key];
    return acc;
  }, {});

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Example

This example shows how to sort an object by its keys alphabetically and create a new sorted object.

javascript

const obj = { banana: 2, apple: 5, cherry: 3 };

const sortedObj = Object.keys(obj)
  .sort()
  .reduce((acc, key) => {
    acc[key] = obj[key];
    return acc;
  }, {});

console.log(sortedObj);

Output

{"apple":5,"banana":2,"cherry":3}

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Common Pitfalls

One common mistake is trying to sort the object directly, but JavaScript objects do not maintain order reliably. Sorting keys and creating a new object is necessary.

Another pitfall is modifying the original object, which is not recommended if you want to keep data safe.

javascript

const obj = { b: 1, a: 2 };

// Wrong: sorting keys but not creating new object
obj.sort(); // Error: obj.sort is not a function

// Right: create new sorted object
const sortedObj = Object.keys(obj)
  .sort()
  .reduce((acc, key) => {
    acc[key] = obj[key];
    return acc;
  }, {});

console.log(sortedObj);

Output

{"a":2,"b":1}

📊

Quick Reference

Object.keys(obj): Get all keys from the object.
keys.sort(): Sort keys alphabetically.
Array.reduce(): Build a new object with sorted keys.
Original object remains unchanged.

✅

Key Takeaways

Use Object.keys() and sort() to get sorted keys of an object.

Create a new object with sorted keys to maintain order.

Do not try to sort the object directly; objects do not guarantee key order.

Keep the original object unchanged for safer code.

Use reduce() to build the sorted object cleanly and simply.