@rxap/utilities/src/lib/array/unique.d.ts

A collection of utility functions, types and interfaces.

/**
 * Represents a function that compares two values of the same type and determines their equality.
 *
 * @callback CompareTo
 * @template T - The type of the elements to compare.
 * @param {T} a - The first element to compare.
 * @param {T} b - The second element to compare.
 * @returns {boolean} - A boolean indicating whether the two elements are equal based on the comparison logic.
 */
export type CompareTo<T> = (a: T, b: T) => boolean;
/**
 * Creates a function that can be used as a predicate to filter unique elements in an array.
 * It checks if the current element's index matches its first occurrence index within the array.
 *
 * @return A function that determines whether a given element is unique in an array.
 */
export declare function unique<T>(): (value: T, index: number, self: T[]) => boolean;
/**
 * Creates a function that can be used to filter an array of objects, ensuring
 * that objects with the same combination of specified property values appear only once.
 *
 * @template T The type of elements in the array. It can be any valid TypeScript type.
 *
 * @param {Array<keyof T>} propertyKeys - An array of property keys used to determine uniqueness.
 * @return {(value: T, index: number, self: T[]) => boolean} A predicate function that returns true for the first occurrence of an object
 * with unique values for the specified properties and false for subsequent occurrences.
 */
export declare function unique<T>(propertyKeys: Array<keyof T>): (value: T, index: number, self: T[]) => boolean;
/**
 * Generates a predicate function to filter unique elements in an array based on a comparison function.
 *
 * @param compareTo - A comparison function that determines if two elements are considered equal.
 * @return A predicate function that can be used in array filtering to retain unique elements.
 */
export declare function unique<T>(compareTo: CompareTo<T>): (value: T, index: number, self: T[]) => boolean;