(Lianja) Get the Index of a JSON Member

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
    }
}

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loJson = createobject("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. 
lcJsonStr = '{"name": "donut","image":{"fname": "donut.jpg","w": 200,"h": 200},"thumbnail":{"fname": "donutThumb.jpg","w": 32,"h": 32}}'

llSuccess = loJson.Load(lcJsonStr)
if (llSuccess <> .T.) then
    ? loJson.LastErrorText
    release loJson
    return
endif

// The top-level JSON object has three members: name, image, and thumbnail.
lnNameIndex = loJson.IndexOf("name")
// The index of the "name" member is 0.
? "nameIndex = " + str(lnNameIndex)

lnThumbIndex = loJson.IndexOf("thumbnail")
// The index of the "thumbnail" member is 2.
? "thumbIndex = " + str(lnThumbIndex)

// 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).
lnFnameIndex = loJson.IndexOf("fname")
// The fnameIndex is -1 (not found).  This is correct.
? "fnameIndex = " + str(lnFnameIndex)

// Get the "image" object.
loImageObj = loJson.ObjectOf("image")
if (loJson.LastMethodSuccess = .F.) then
    ? "image object not found."
    release loJson
    return
endif

// Now we can get the index of the "fname" object, because it is a direct
// member of the "image" object:
lnFnameIndex = loImageObj.IndexOf("fname")
? "fnameIndex = " + str(lnFnameIndex)

release loImageObj


release loJson