Laravel + Vue Error in render: "SyntaxError: Unexpected token u in JSON at position 0" - json

Question

I have a Laravel application with Vue js and until a while ago it was working perfectly. Now when I go to any page that uses Vue js this error appears: [Vue warn]: Error in render: "SyntaxError: Unexpected token u in JSON at position 0".
When I reload the page by clearing the cache (Control + Shift + R on Mac OS) it works again, but when I update without this command the error appears again.
PS: I didn't do any package updates for both laravel and npm, it just stopped working out of nowhere.

Answer 1

Try this in the console:
JSON.parse(undefined)
Here is what you will get:
Uncaught SyntaxError: Unexpected token u in JSON at position 0
at JSON.parse (<anonymous>)
at <anonymous>:1:6
In other words, your app is attempting to parse undefined, which is not valid JSON.
There are two common causes for this. The first is that you may be referencing a non-existent property (or even a non-existent variable if not in strict mode).
window.foobar = '{"some":"data"}';
JSON.parse(window.foobarn) // oops, misspelled!
The second common cause is failure to receive the JSON in the first place, which could be caused by client side scripts that ignore errors and send a request when they shouldn't.
Make sure both your server-side and client-side scripts are running in strict mode and lint them using ESLint. This will give you pretty good confidence that there are no typos.
Sometime it is becaseu of this let data = JSON.parse(this.response); so try to change it to
let data = JSON.parse(this.responseText);
I really did was change this.response to this.responseText