helabenkhalfallah

const converterOld = (toUnit, factor, offset, input) => {
  const converterOffset = offset || 0;
  return [((converterOffset + input) * factor).toFixed(2), toUnit].join(' ');
};

const convert10MilesToKm = converterOld('km', 1.60936, undefined, 10);
const convert20MilesToKm = converterOld('km', 1.60936, undefined, 20);
const convert30MilesToKm = converterOld('km', 1.60936, undefined, 30);

console.log('convert10MilesToKm : ', convert10MilesToKm); //  "16.09 km"

helabenkhalfallah

const converterOld = (toUnit, factor, offset, input) => {
  const converterOffset = offset || 0;
  return [((converterOffset + input) * factor).toFixed(2), toUnit].join(' ');
};

const convert10MilesToKm = converterOld('km', 1.60936, undefined, 10);
const convert20MilesToKm = converterOld('km', 1.60936, undefined, 20);
const convert30MilesToKm = converterOld('km', 1.60936, undefined, 30);

console.log('convert10MilesToKm : ', convert10MilesToKm); //  "16.09 km"

helabenkhalfallah

const playWithArray = () => {
  let privateArray = [];

  const addItem = (item) => {
    privateArray.push(item);
  }
  
  const removeItem = (index) => {
    privateArray.splice(index, 1);
  }

helabenkhalfallah

const counter = () => {
  let privateCounter = 0;
  
  const changeBy = (val) => {
    privateCounter += val;
  }
  
  return ({
    increment: () => {
      changeBy(1);

helabenkhalfallah

const outerFunc = () =>  {
  // the outer scope
  let outerVar = 'I am from outside!';

  const innerFunc = () => {
    // the inner scope
    console.log(outerVar);
  }

  return innerFunc;

helabenkhalfallah

const globalVar = 'global';

const outerFunc = () => {
  const outerVar = 'outer';

  const innerFunc = () => {
    const innerVar = 'inner'
    console.log(innerVar, outerVar, globalVar); // "inner", "outer", "global"
  }

helabenkhalfallah

const outerFunc = () => {
  // function scope
  const message = 'Hi, Hela !';

  {
    // block scope
    const message = 'Hello !';
    console.log('inside message : ', message); // "inside message : ", "Hello !"
  }

helabenkhalfallah

const run = () => {
  // "run" function scope
  const two = 2;
  let count = 0;
  const run2 = () => { }

  console.log(two);   // 2
  console.log(count); // 0
  console.log(run2);  // function
}