Extract a value from a json object by its key, return defaultVal if key not found.
Substitute default values when keys aren't present.
auto aa = ["a": 1, "b": 2]; auto json = JSONValue(aa); assert(json.fromJSON!int("a", 7) == 1); assert(json.fromJSON!int("c", 7) == 7);
See Implementation
Extract a value from a json object by its key, return defaultVal if key not found.