bhaveshdaswani93

// Our task is to multiply a number  with 3 and take absolute of that number
const multiplyWith3  = (x)=>x*3;
const getAbsouleOfNum = (x)=>Math.abs(x)
// here we have two component multiplyWith3 and getAbsouleOfNum 
// if we want to do that without compose we will do like these
let x = 15;
let xAfterMultiply = multiplyWith3(x);
let xAfterAbsoulte = getAbsouleOfNum(xAfterMultiply);

//Let's do in composable way

bhaveshdaswani93

const notMemoized = (x) => {
  return x*2;
}

notMemoized(2); // 4
notMemoized(2); // 4
// every time we run the function the multiplication code get executed which can be optimized by memoization

const memoizedFn = () => {
  const cache = {};

bhaveshdaswani93

const multiply = (a,b,c) =>a*b*c;

//Partial Application
const partiallyMultiplyBy5 = multiply.bind(null,5);
partiallyMultiplyBy5(4,10) //200
// in above example  partiallyMultiplyBy5 partially apply multiply function with 5 as first argument.
// when executing the partiallyMultiplyBy5 function we just have to pass remaining paramater as the first argument 5 has been remember
// due to closure.

bhaveshdaswani93

const multiply = (a,b) => a*b;
multiply(4,6) // 24
//above is the function that take multiple argument let convert into curring
const curring = (a)=>(b)=>a*b;
curring(5)(4); // 20

// we have converted multiply function that take 2 param 
// into two function that takes one parameter at a time

bhaveshdaswani93

const hocFn = function() {
  return function() {
    return 5;
  }
}
hocFn() // will return function
hocFn()() // will return 5
// hocFn return function so it is HOC

const fn = function(x) {

bhaveshdaswani93

let mutateObj = {
  first_name:'lorem',
  last_name:'ipsum'
};

let immutateObj = {
  first_name:'irum',
  last_name:'egestas'
};

bhaveshdaswani93

//Imperative: what to do and how to do
//Declarative: what to do and what should be done

// Task i want to loop through 1 to 5 and print in the console let see how we can do the code impertively as well as declaratively

//Imerative
for(i=1;i<=5;i++) {
  console.log(i);
}
/*

bhaveshdaswani93

//here i will try to explain a key concept idempotence with example
function notIdempotenceFn(num) {
  return Math.random(num);
}

notIdempotenceFn(5);
notIdempotenceFn(5);
// the output of above two function will be differeht however passing the same input so the function is not idempotent

function idempotentFn(num) {

bhaveshdaswani93

let a = (num1,num2) => {
  return num1+num2;
}

let b = (num) => {
  return num*2;
}

console.log(b(a(3,4))) //output will be 14
// here i can replace a(3,4) expression with value 7 value and this will not effect to the result of the program because its return

bhaveshdaswani93

function addTwoNumber(num1,num2) {
  return num1 + num2;
}

addTwoNmber(3,4); // will return 7 no matter how many times is called

function multiplyWithCurrentTime(num) {
  return num * new Date().getTime();
}