The existsByPath method checks whether a specified path exists in the JSON array.
existsByPath( path )
| Argument | Description | 
|---|---|
| path | (string) The path to check. Construct the path from array indexes and object attribute names, and use a slash ( /) as the separator. If an object attribute name includes a slash, then escape the slash with a backslash, for example"one\\/two". Notice that you must also escape a backslash with another backslash. | 
(Boolean) Returns true if the path exists, false otherwise.
local myJsonObject = LuaJsonObject:new( { product="IDOL" , version=11 } )
local myJsonArray = LuaJsonArray:new("zero",1,2,myJsonObject)
print (myJsonArray:existsByPath("3/product"))
-- true (LuaJsonArrays are zero-indexed)
        |  |