type PrimitiveType = number | string | boolean;
/** Object types that should never be mapped */
type AtomicObject = Function | Promise<any> | Date | RegExp;
/**
 * If the lib "ES2015.Collection" is not included in tsconfig.json,
 * types like ReadonlyArray, WeakMap etc. fall back to `any` (specified nowhere)
 * or `{}` (from the node types), in both cases entering an infinite recursion in
 * pattern matching type mappings
 * This type can be used to cast these types to `void` in these cases.
 */
type IfAvailable<T, Fallback = void> = true | false extends (T extends never ? true : false) ? Fallback : keyof T extends never ? Fallback : T;
/**
 * These should also never be mapped but must be tested after regular Map and
 * Set
 */
type WeakReferences = IfAvailable<WeakMap<any, any>> | IfAvailable<WeakSet<any>>;
type WritableDraft<T> = {
    -readonly [K in keyof T]: Draft<T[K]>;
};
/** Convert a readonly type into a mutable type, if possible */
type Draft<T> = T extends PrimitiveType ? T : T extends AtomicObject ? T : T extends ReadonlyMap<infer K, infer V> ? Map<Draft<K>, Draft<V>> : T extends ReadonlySet<infer V> ? Set<Draft<V>> : T extends WeakReferences ? T : T extends object ? WritableDraft<T> : T;

export type { WritableDraft as W };