/**
 * Return b's the occurrence percentage in a.
 * The ordering of a & b matters.
 */
declare function intersectionPercentage<T>(a: T[], b: T[]): number;
declare function toObject<T, V>(array: ReadonlyArray<T>, mapperCallback: (item: T, index: number) => [string, V]): {
    [key: string]: V;
};
/**
 * Accepts a list of item and a callback, maps each item with the callback,
 * then removes value of `null`, `undefined`, `NaN` from the resulting list.
 * Other falsy values are **NOT** removed.
 *
 * @param array    List of items to be filtered
 * @param callback Callback to transform item
 */
declare function compactMap<T, V>(array: ReadonlyArray<T>, callback: (item: T, index: number) => V): Array<NonNullable<V>>;
/**
 * If element exists in array, it will return a new array without this element.
 * If element not exists in array, it will return a new array with this element in the last.
 */
declare function toggleElement<T>(array: ReadonlyArray<T>, element: T): T[];
export declare const ArrayUtil: Readonly<{
    intersectionPercentage: typeof intersectionPercentage;
    toObject: typeof toObject;
    compactMap: typeof compactMap;
    toggleElement: typeof toggleElement;
}>;
export {};