Json Parse in Javascript

To decode a JSON-string, we need another method named JSON.parse
For instance:

1
2  let numbers="[0,1,2,3]"; 
3  numbers=JSON.parse(numbers)
4  alert(numbers[1])
5

Or for nested objects

1let userData = '{ "name": "John", "age": 35, "isAdmin": false, "friends": [0,1,2,3] }';
2  let user = JSON.parse(userData);
3  alert( user.friends[1] )

Reviver

Optional function(key,value) that will be called for each (key, value) pair and can transform the value

Using Reviver

1let str = '{"title":"Conference","date":"2017-11-30T12:00:00.000Z"}';
2  let meetup = JSON.parse(str, function(key, value) {
3  if (key == 'date') return new Date(value);
4  return value;
5  });
6     alert( meetup.date.getDate() );

1 let schedule = {
2        "meetups": [
3        {"title":"Conference","date":"2017-11-30T12:00:00.000Z"},
4        {"title":"Birthday","date":"2017-04-18T12:00:00.000Z"}
5        ]
6        };
7        schedule = JSON.parse(schedule, function(key, value) {
8            if (key == 'date') return new Date(value);
9            return value;
10            });
11            alert( schedule.meetups[1].date.getDate() ); 
12