tom-weatherhead/common-utilities.ts

// github:tom-weatherhead/common-utilities.ts/src/lazy.ts

import { cloneArray } from './arrays';

function pushMe<T>(array: T[], element: T): T[] {
    array.push(element);

    return array;
}

// Here, fn can be an n-ary function, not just a binary function:

export function makeLazyList(fn: (...args: unknown[]) => unknown, ...args: unknown[]): unknown {
    // const argsClone = args.slice(0); // See https://davidwalsh.name/javascript-clone-array
    const argsClone = cloneArray(args);
    const arg1 = args.shift();

    return () => [arg1, makeLazyList(fn, ...pushMe(args, fn(...argsClone)))];
}