@politie/sherlock-utils/src/pairwise.d.ts

Utility functions that are designed to work with Sherlock. His toolbelt.

/**
 * Calls the provided dyadic function with respectively the current and previous value that was received by the returned monadic function.
 * In other words, when you wrap a function with wrapPreviousState you not only get the current value, but also the previous one (as a
 * second parameter).
 *
 * @param f the function to wrap
 */
export declare function pairwise<V, R>(f: (newValue: V, oldValue?: V) => R): (value: V) => R;
/**
 * Calls the provided dyadic function with respectively the current and previous value that was received by the returned monadic function.
 * In other words, when you wrap a function with wrapPreviousState you not only get the current value, but also the previous one (as a
 * second parameter).
 *
 * @param f the function to wrap
 * @param init the value to use the first time as second argument to `f`.
 */
export declare function pairwise<V, R>(f: (newValue: V, oldValue: V) => R, init: V): (value: V) => R;