Fix Unexpected token o in JSON at position 1 error in JS

avatar

Borislav Hadzhiev

Last updated: Jul 25, 2022

banner

Check out my new book

Fix Unexpected token o in JSON at position 1 error #

The "Unexpected token o in JSON at position 1" error occurs when we try to JSON.parse a value that is not a valid JSON string, e.g. a native JavaScript object. To solve the error, use the JSON.stringify() method if you need to convert a value to JSON.

unexpected token o in json at position 1

Here is an example of when the error occurs:

index.js
// ⛔️ Unexpected token o in JSON at position 1 JSON.parse({}); // ⛔️ (if using jQuery) $.parseJSON({})

We passed a native JavaScript object to the JSON.parse method.

If the value is already a native JavaScript value (not JSON), you don't have to use the JSON.parse or $.parseJSON methods. You can use the value in your code as is.

If you're trying to convert a value to JSON, use the JSON.stringify() method instead:

index.js
// ✅ is now valid JSON string const json = JSON.stringify({name: 'Tom'});

The JSON.stringify() method converts a native JavaScript value to a JSON string.

If you're trying to parse a JSON string to a native JavaScript value, you have to make sure the value is valid JSON before parsing it or you can use a try/catch block to handle any errors.

If the value is JSON, then it must be of type string.

index.js
console.log(typeof {}); // 👉️ "object" console.log(typeof JSON.stringify([1])); // 👉️ "string"

Here's an example of how to use a try/catch block to handle a possible error when parsing a value.

index.js
try { const parsed = JSON.parse({}); } catch (err) { // ⛔️ Unexpected token o in JSON at position 1 console.log(err.message); }

We call the JSON.parse method inside of a try/catch block. If passed an invalid JSON value, the method will throw an error, which will get passed to the catch() function.

You can handle the error in the catch function as you see fit.

If you are expecting valid JSON from your server, you can console.log the response from your server and its type using the typeof operator.

If your server is not sending valid JSON, make sure to set the Content-Type header to application/json on your server side.

You can paste the JSON value into an online JSON validator and see if it passes the test.

The validator would show you if there are any errors in the JSON and where the errors are.

If the value is malformed or not valid JSON, you have to format it correctly before passing it to the JSON.parse method.

Use the search field on my Home Page to filter through my more than 3,000 articles.