DefinitelyTyped/compose-function/index.d.ts

// Type definitions for compose-function
// Project: https://github.com/stoeffel/compose-function
// Definitions by: Denis Sokolov <https://github.com/denis-sokolov>
// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped


// Hardcoded signatures for 2-4 parameters
declare function f<A, B, C>(
    f1: (b: B) => C,
    f2: (a: A) => B
): (a: A) => C;
declare function f<A, B, C, D>(
    f1: (b: C) => D,
    f2: (a: B) => C,
    f3: (a: A) => B
): (a: A) => D;
declare function f<A, B, C, D, E>(
    f1: (b: D) => E,
    f2: (a: C) => D,
    f3: (a: B) => C,
    f4: (a: A) => B
): (a: A) => E;

// Minimal typing for more than 4 parameters
declare function f<Result>(
    f1: (a: any) => Result,
    ...functions: Function[]
): (a: any) => Result;

export = f;