JavaScript

Get the Index of a JSON Member

See more JSON Examples

This example demonstrates how to get the index of a given member by name.

{
  "name": "donut",
  "image":
    {
    "fname": "donut.jpg",
    "w": 200,
    "h": 200
    },
  "thumbnail":
    {
    "fname": "donutThumb.jpg",
    "w": 32,
    "h": 32
    }
}

JavaScript

var success = false;

var json = new CkJsonObject();

// This is the above JSON with whitespace chars removed (SPACE, TAB, CR, and LF chars).
// The presence of whitespace chars for pretty-printing makes no difference to the Load
// method. 
var jsonStr = "{\"name\": \"donut\",\"image\":{\"fname\": \"donut.jpg\",\"w\": 200,\"h\": 200},\"thumbnail\":{\"fname\": \"donutThumb.jpg\",\"w\": 32,\"h\": 32}}";

success = json.Load(jsonStr);
if (success == false) {
    console.log(json.LastErrorText);
    return;
}

// The top-level JSON object has three members: name, image, and thumbnail.
var nameIndex = json.IndexOf("name");
// The index of the "name" member is 0.
console.log("nameIndex = " + nameIndex);

var thumbIndex = json.IndexOf("thumbnail");
// The index of the "thumbnail" member is 2.
console.log("thumbIndex = " + thumbIndex);

// The "fname" member is NOT a direct member of the top-level JSON object.
// It is a member of a nested object.  If we try to get the index of this
// member using the top-level JSON object, it is not found (and returns -1).
var fnameIndex = json.IndexOf("fname");
// The fnameIndex is -1 (not found).  This is correct.
console.log("fnameIndex = " + fnameIndex);

// Get the "image" object.
var imageObj = new CkJsonObject();
json.ObjectOf2("image",imageObj);

// Now we can get the index of the "fname" object, because it is a direct
// member of the "image" object:
fnameIndex = imageObj.IndexOf("fname");
console.log("fnameIndex = " + fnameIndex);