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Anybody Please explain what is difference between two codes. i am trying to print JSON String.

1) console.log("Hello "+str);

2) 

console.log("Hello");
console.log(str);

and this is working

this code is giving error console.log("Hello "+str); Converting circular structure to JSON

Why it is happening. Can anybody explain me what is difference in both code.

EDIT: this is my code 

firstname="hello"; 
lastname= "hhf";
username= "dffflffl";
email="email@hitemai.com
password= "dddd";

var opts = { 
url: 'localhost:8081/register', 
method: 'POST', 
body: JSON.stringify({first_name:firstname,last_name:lastname, user_name:username,email:email,password:password}), 

};

Thanks

Hitu Bansal
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2 Answers2

1

JSON cannot handle self-referential objects (cyclic object graphs), so such a thing cannot be printed by the console.

> var str = { x : 1}; str.x = str;
> JSON.stringify(str);

TypeError: cyclic object value
Thilo
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0

If str is supposed to be a JSON string produced by JSON.stringify, then you would get that error if the object you're converting to JSON has a reference to itself or child objects with circular references.

See: Chrome sendrequest error: TypeError: Converting circular structure to JSON.

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jfairbank
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