three js SyntaxError: Unexpected token < in JSON at position 0 code example

Example 1: Uncaught (in promise) SyntaxError: Unexpected token O in JSON at position 0

var stringified = JSON.stringify(data);
var parsedObj = JSON.parse(stringified);
 
console.log(parsedObj);

Example 2: unexpected token s in json at position 0

var s = '"something"';
var result = JSON.parse(s);