By Vishal Basumatary in javascript — Mar 24, 2023

JSON stringify not sorting correctly

If you are facing an issue where JSON.stringify is not sorting your JSON object in the expected order, then you are not alone. This issue is quite common, and it happens because the order of the properties in an object is not guaranteed in JavaScript.

Here is an example:


const obj = { b: 2, c: 3, a: 1 };
console.log(JSON.stringify(obj)); // {"b":2,"c":3,"a":1}

As you can see, the properties of the object are not sorted in the order they were defined, and this can cause issues when trying to compare or hash JSON objects.

Solution 1: Use a sorting function

To solve this issue, you can use a sorting function to sort the keys of the object before stringifying it. Here is an example:


const obj = { b: 2, c: 3, a: 1 };
const sortedObj = Object.keys(obj).sort().reduce((acc, key) => ({ ...acc, [key]: obj[key] }), {});
console.log(JSON.stringify(sortedObj)); // {"a":1,"b":2,"c":3}

In this example, we first get the keys of the object using Object.keys, sort them using .sort(), and then use .reduce() to create a new sorted object from the original object.

Solution 2: Use a custom replacer function

Another way to solve this issue is to use a custom replacer function in JSON.stringify that sorts the object keys before stringifying them. Here is an example:


const obj = { b: 2, c: 3, a: 1 };
const sortedStringify = (obj) => JSON.stringify(obj, Object.keys(obj).sort());
console.log(sortedStringify(obj)); // {"a":1,"b":2,"c":3}

In this example, we pass a sorting function as the second argument to JSON.stringify, which sorts the keys of the object before stringifying them.

Conclusion

Sorting JSON objects can be a bit tricky in JavaScript, but with the right tools, it's not impossible. By using a sorting function or a custom replacer function in JSON.stringify, you can ensure that your JSON objects are always sorted in the expected order.