recursive

recursive.js

const util = require("util");

// RECURSIVE FUNCTIONS: pow, fibonaci, factorial, map, reverse

const pow = (b, n) => (n === 1 ? b : b * pow(b, n - 1));

const fibonaci = x => (x <= 1 ? 1 : fibonaci(x - 1) + fibonaci(x - 2));

const factorial = x => (x === 1 ? 1 : x * factorial(x - 1));

const map = (arr, fn) => (arr.length === 0 ? [] : [fn(arr[0])].concat(map(arr.slice(1), fn)));

const reverse = s => (s.length === 1 ? s : s.slice(-1) + reverse(s.slice(0, -1)));

const sumSalaries = department => {
  const isDepartment = Array.isArray(department);

  if (isDepartment) {
    return department.reduce((acc, dept) => acc + dept.salary, 0);
  } else {
    let sum = 0;
    for (let dept in department) {
      sum += sumSalaries(department[dept]);
      console.log(`${dept}: ${sum}`);
    }
    return sum;
  }
};

const title = title => console.log(`\n${title}\n-----------------------`);

const iterate = (fnName, fn) => {
  [1, 2, 3, 4, 5].forEach(n => console.log(`${fnName}(${n}) = ${fn(n)}`));
};

title("power-of-base2");
iterate("powOfBase2", x => pow(2, x));

title("fibonaci");
iterate("fib", fibonaci);

title("factorial");
iterate("factorial", factorial);

// map
title("map");
const upperCase = x => x.toUpperCase();
const charArray = "abcde".split("");
console.log(util.format("map(%j, upperCase) = %j", charArray, map(charArray, upperCase)));

// reverse
title("reverse");
const string = "abcdef";
console.log(`reverse(${string}) = ${reverse(string)}`);

// sumSalaries
title("sum salaries");
const company = {
  sales: [{ name: "John", salary: 1000 }, { name: "Alice", salary: 600 }],
  development: {
    sites: [{ name: "Peter", salary: 2000 }, { name: "Alex", salary: 1800 }],
    internals: [{ name: "Jack", salary: 1300 }]
  }
};
console.log("sumSalaries(company): ");
console.log(`total: ${sumSalaries(company)}`);