sequency/lib/associateBy.d.ts

Functional sequences for processing iterable data in JavaScript

export declare class AssociateBy<T> {
    /**
     * Returns a map consisting of the elements mapped by the given `keySelector`.
     *
     * @param {(value: T) => K} keySelector
     * @returns {Map<K, T>}
     */
    associateBy<K>(keySelector: (value: T) => K): Map<K, T>;
    /**
     * Returns a map consisting of the elements indexed by the given `key`.
     *
     * @param {K} key
     * @returns {Map<T[K], T>}
     */
    associateBy<K extends keyof T>(key: K): Map<T[K], T>;
    /**
     * Returns a map consisting of the elements mapped by the given `keySelector`. The value
     * is transformed into another value by the `valueTransformer`.
     *
     * @param {(value: T) => K} keySelector
     * @param {(value: T) => V} valueTransformer
     * @returns {Map<K, V>}
     */
    associateBy<K, V>(keySelector: (value: T) => K, valueTransformer: (value: T) => V): Map<K, V>;
    /**
     * Returns a map consisting of the elements indexed by the given `key`. The value
     * is transformed into another value by the `valueTransformer`.
     *
     * @param {K} key
     * @param {(value: T) => V} valueTransformer
     * @returns {Map<K, V>}
     */
    associateBy<K extends keyof T, V>(key: K, valueTransformer: (value: T) => V): Map<T[K], V>;
}