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const multiply20 = (price) => price * 20;
const divide100 = (price) => price / 100;
const normalizePrice = (price) => price.toFixed(2);

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// result = a(b(c(x)))
const discount = normalizePrice(divide100(multiply20(200))); // 40.00

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const compose = (a, b, c) => (x) => a(b(c(x)));

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const discount = compose(normalizePrice, divide100, multiply20);
discount(200.0); //40.00

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const compose =
  (...fns) =>
  (x) =>
    fns.reduceRight((res, fn) => fn(res), x);

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const addPrefix = (price) => "$" + String(price); //$ 40.00
const discountWithPrefix = compose(
  addPrefix,
  normalizePrice,
  divide100,
  multiply20
);
discountWithPrefix(200.0); // '$40.00'

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const pipe =
  (...fns) =>
  (x) =>
    fns.reduce((res, fn) => fn(res), x);

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const multiply20 = (price) => price * 20;
const divide100 = (price) => price / 100;
const normalizePrice = (price) => price.toFixed(2);
const addPrefix = (price) => "$" + String(price);

const pipe =
  (...fns) =>
  (x) =>
    fns.reduce((res, fn) => fn(res), x);
const compose =

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// Result is [2,3,4]
[1,2,3].map((number)=>number+1)

// Note that you can extract the callback function and pass it to the map function:
function addOne(arg){
    return arg+1
}

[1,2,3].map((number)=>addOne(number))
// or

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// We first define the function we will be using as an argument
const addOne = (arg)=>arg+1

// We than define our hof
const higherOrderFunction = (fn, arg) => fn(arg)*2
 
// The result will be 12
higherOrderFunction(addOne, 5)