Simple ES6 'map' sample

readme.md

map

Map allows us to apply an operation to each item of an array, returning a new array that contains the items with the operation applied.

This can save us lot of "for" loops (enhannce readibility).

steps

Let's implement a function that will apply a discount all the elements of a given array.

Usually we would do something like:

const sales = [20, 30 ,25];


function applyDiscount(sales, discount) {
  let discountedSales = [];

  for(let i=0;i< sales.length;i++) {
    discountedSales.push(sales[i] * (1 - (discount / 100)));
  }
  
  return discountedSales;
}

console.log(applyDiscount(sales, 10));

By Using map:

const sales = [20, 30 ,25];

function applyDiscount(sales, discount) {
  return sales.map((sale) => sale * (1 - (discount / 100))
}

console.log(applyDiscount(sales, 10));

usingES5.js

const sales = [20, 30 ,25];


function applyDiscount(sales, discount) {
  let discountedSales = [];

  for(let i=0;i< sales.length;i++) {
    discountedSales.push(sales[i] * (1 - (discount / 100)));
  }
  
  return discountedSales;
}

console.log(applyDiscount(sales, 10));

usingMapES6.js

const sales = [20, 30 ,25];

function applyDiscount(sales, discount) {
  return sales.map((sale) => sale * (1 - (discount / 100))
}

console.log(applyDiscount(sales, 10));