var arr1 = [1, 2, 3, undefined, 4, 5];
var arr2 = JSON.parse(JSON.stringify(arr1));
console.log(arr2);
Output of the above code will be....
[1, 2, 3, null, 4, 5]
Why it converts it's 4th value from "undefined" to "null"?
After cloning JS array using JSON.parse & JSON.stringify, why array's "undefined" value converts to "null"?
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1 Answers
Because undefined is a Javascript type. There is no undefined in JSON.
According to the spec:
JSON can represent four primitive types (strings, numbers, booleans, and null) and two structured types (objects and arrays).
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