/**
 * Used internally by `keyby`, `groupby`, and others to normalize the key argument and
 * determine how to extract the value from an object
 *
 * If the key is a string, the txstate-utils `get` function is used to extract the value
 * If the key is a function, the function is used to extract the value
 * If the key is a number or symbol, the value is extracted directly
 * If the key is undefined, the object itself is returned instead of having a value extracted
 */
export declare const extractors: Record<string, (arg: any) => ((obj: any) => any)>;