Customization

Custom serializers and deserializers

Custom methods are useful when:

• a type has a compact wire format
• you need backward-compatible custom JSON
• you want a built-in container subclass to use a different representation

Best practices

• always return valid JSON text
• always create a fresh object in custom deserializers
• prefer a narrow JSON kind like "string" when possible
• use JSON.parse<T>(...) and JSON.stringify(...) normally inside the custom method; the transform will route nested calls through JSON.internal

Built-in subclass overrides

Decorated subclasses of built-in containers can override the built-in format with custom methods.

Examples that work well:

• Uint8Array encoded as a hex string
• Array<i32> encoded as a CSV string
• Map<string, i32> encoded as tagged string data
• Set<string> encoded as custom compact string data