Lua Requires Chilkat v11.0.0+

Get the Root of a JSON Document

See more JSON Examples

Demonstrates how to get back to the JSON root object from anywhere in the JSON document. This example uses the following JSON document:

{
  "flower": "tulip",
  "abc":
    {
    "x": [
       { "a" : 1 },
       { "b1" : 100, "b2" : 200 },
       { "c" : 3 }
    ],
    "y": 200,
    "z": 200
    }
}

Lua

local chilkat = require("chilkat")

local json = chilkat.JsonObject.new()

local jsonStr = "{\"flower\": \"tulip\",\"abc\":{\"x\": [{ \"a\" : 1 },{ \"b1\" : 100, \"b2\" : 200 },{ \"c\" : 3 }],\"y\": 200,\"z\": 200}}"

local success = json:load(jsonStr)
if not success then
    print(json.last_error_text)
    return
end

-- Get the "abc" object.
local abcObj = chilkat.JsonObject.new()
success = json:object_of2("abc", abcObj)
if not success then
    print(json.last_error_text)
    return
end

-- Side note: The JSON of a sub-part of the document can be emitted from any JSON object:
abcObj.emit_compact = false
print(abcObj:emit())

-- Navigate to the "x" array
local xArray = chilkat.JsonArray.new()
abcObj:array_of2("x", xArray)

-- Navigate to the 2nd object contained within the array.  This contains members b1 and b2
local bObj = chilkat.JsonObject.new()
xArray:object_at2(1, bObj)

-- Show that we're at "b1/b2".
-- The value of "b1" should be "200"
print("b2 = " .. bObj:int_of("b2"))

-- Now go back to the JSON doc root:
local docRoot = chilkat.JsonObject.new()
bObj:get_doc_root2(docRoot)

-- We'll skip the null check and assume it's non-null...

-- Pretty-print the JSON doc from the root to show that this is indeed the root.
docRoot.emit_compact = false
print(docRoot:emit())