Exercise from Kyle Simpson's Functional-Lite programming course

addnMapReduce.js

function addnMapReduce(...args) {
    // Can do args.slice(1).reduce(..., args[0]) to skip num(0) no-op
    return args.reduce((prev, cur) => () => add2(prev, cur), num(0))();
}

function num(number) {
    return () => number;
}

function add2(fn1, fn2) {
    return add(fn1(), fn2());
}

function add(a, b) {
    return a + b;
}

function num1() {
    return 10;
}

function num2() {
    return 7;
}