pizza_example_v2.js

const _pipe = (a, b) => (arg) => b(a(arg));
const pipe = (...ops) => ops.reduce(_pipe)

const calcTotalWithTax = pizzaCost => pizzaCost * 1.13
const costForTwo = itemCost => Math.round(itemCost/2 * 100) / 100
const cadToUSD = (cad) => Math.round(cad * 0.753653*100)/100;
const costPerPersonUsd = pipe(calcTotalWithTax, costForTwo, cadToUSD);
console.log(`You have to pay $ ${costPerPersonUsd(5)} US.`); // You have to pay $2.13 in usd


// Behind the scene: 
const costPerPersonUsd = (calcTotalWithTax, costForTwo, cadToUSD)
1. _pipe(calcTotalWithTax, costForTwo) `would be` (args) => costForTwo(calcTotalWithTax(arg)) // We will call the bundled function pipe1
2a.  _pipe((args) =>  costForTwo(calcTotalWithTax(arg), cadToUSD)` would be` (arg) => cadToUsd( costForTwo(calcTotalWithTax(arg))
// or  _pipe(pipe1, cadToUSD) would become  (arg) => cadToUsd( costForTwo(calcTotalWithTax(arg))                                                                         
3. costPerPersonUsd `would be` (args) => cadToUsd( costForTwo(calcTotalWithTax(arg))