//#region src/tag.d.ts
/**
* Property key used to brand objects with a tag string.
*
* Defined via `Object.defineProperty` as non-enumerable, non-writable, and
* non-configurable, so it does not appear in `Object.keys`, `JSON.stringify`,
* `for...in`, or spread.
*/
declare const TAG: "__tag";
/**
* Nominal type brand that carries a tag string on the {@link TAG} property.
*
* @private
*/
interface NominalTag<TTag extends string> {
  readonly [TAG]: TTag;
}
/**
* Intersect a plain object type with a nominal tag brand.
*
* Used to brand plain data objects with a discriminator that is hidden from
* enumeration, serialization, and spread — while remaining accessible via
* the {@link TAG} key for runtime type-narrowing.
*/
type Tagged<TObj extends object, TTag extends string> = TObj & NominalTag<TTag>;
/**
* Create a shallow copy of `obj` with a non-enumerable {@link TAG} property.
*
* The original object is not mutated. The tag is defined as non-enumerable,
* non-writable, and non-configurable via `Object.defineProperty`.
*
* @param obj - The source object to copy and tag.
* @param tag - The tag string to brand the copy with.
* @returns A new object with all own enumerable properties of `obj` plus the hidden tag.
*/
declare function withTag<TTag extends string, TObj extends object>(obj: TObj, tag: TTag): Tagged<TObj, TTag>;
/**
* Type guard that checks whether `value` carries the given tag.
*
* @param value - The value to inspect.
* @param tag - The expected tag string.
* @returns `true` when `value` is a non-null object whose `[TAG]` equals `tag`.
*/
declare function hasTag<TTag extends string>(value: unknown, tag: TTag): value is NominalTag<TTag>;
/**
* Read the tag from a value, if present.
*
* @param value - The value to inspect.
* @returns The tag string, or `undefined` when the value is untagged.
*/
declare function getTag(value: unknown): string | undefined;
//#endregion
export { TAG, Tagged, getTag, hasTag, withTag };
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