Question

I can create a Json object as here
How to create json by javascript for loop?
great!
and I have created one like below

[
    {
        "id": "10",
        "userName": "kuttan" 
    },
    {
        "id": "11",
        "userName": "kunjan" 
    }
]

Suppose I want to update name of the user with id 10 to “new name”
what should i do?(i dont know the index is 1)

Answer 1

Loop over your array of objects (because that’s what it is), and check the “id” attribute of each object.

var list =  [ { "id": "10", "userName": "kuttan" }, { "id": "11", "userName": "kunjan" } ];

for (var i=0;i<list.length;i++) {
  if (list[i].id == "10") {
    alert(i);
  };
};

You could then abstract this into some nice function.

function findIndexById(list, id) {
  for (var i=0;i<list.length;i++) {
    if (list[i].id == id) {
      return i;
    };
  };  

  return -1;
};

Then use it as follows:

var list =  [ { "id": "10", "userName": "kuttan" }, { "id": "11", "userName": "kunjan" } ];
var index = findIndexById(list, "10");

if (index !== -1) {
  list[index].userName = "new username";
};