Stringify & Parse.

Theory. The path "object → text → object" is called a round-trip. After JSON.parse you get a NEW object with the same data — not the same one. That is why copy === original is false even if they look equal.

JSON.parse expects valid JSON. The result holds only what JSON can carry: numbers, strings, booleans, null, arrays, plain objects. A Date becomes a string; undefined and functions disappear.

Small examples:

const text = '{"id":1,"title":"Rent","amount":500}'; const data = JSON.parse(text); data.title; // "Rent" JSON.stringify(data) === text; // true for this compact form

Key order is kept, spaces are not: stringify(data) gives compact text unless you pass an indent.

Common mistake: comparing objects with ===; expecting text with single quotes to parse; parsing an already parsed object.