/**
 * This function coerces a string into a string literal type.
 * Using tagged union types in TypeScript 2.0, this enables
 * powerful typechecking of our reducers.
 *
 * Since every action label passes through this function it
 * is a good place to ensure all of our action labels are unique.
 *
 * @param label
 */
export declare const checkActionType: <T>(label: T | '') => T;