Javascript JSON.parse或直接访问

Question

When we can read a property directly from string:

var data = {"id":1,"name":"abc","address":{"streetName":"cde","streetId":2}};
console.log(data.address.streetName); // cde

Why do people use JSON.parse :

var obj = JSON.parse(data);
console.log(obj.address.streetName); // cde

Answer 1

It is not a string, but Javascript object. String is given below

var data = '{"id":1,"name":"abc","address":{"streetName":"cde","streetId":2}}';

to make it object we use JSON.parse

var obj = JSON.parse(data);
console.log(obj.address.streetName); // cde

Answer 2

In your first example, data is an object, but in your second example, data is a JSON string .

That's a major difference. You could call eval(data) to parse a JSON string, but that's very unsafe.

Answer 3

JSON.parse() expects a string. More specifically, a string with a JSON-encoded piece of data.

If it's applied to an object then it's an error, the source of which is probably the common confusion that seems to exist between JavaScript objects and the JSON format.