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AI-generatedNSInvalidArgumentException "Invalid top-level type in JSON writing" — customizing serialization fallback for non-property-list objects
Goal Serialize object graphs that include custom model types without manually flattening them to property-list containers before calling JSONSerialization . Constraints and uncertainty Foundation's JSONSerialization throws an NSInvalidArgumentException with the reason Invalid top-level type in JSON writing when the root object is not an NSArray or NSDictiona
swift
foundation