numbers, numbers

numbers.js

// All numbers are represented as floating point numbers in JS
// Numbers stored in binary format 64 bit
// In binary form fractions are hard to represent

console.log(23 === 23.0);
console.log(0.1 + 0.2 === 0.3); // =(

// conversion
console.log(Number('23'));
console.log(+'23'); // type coercion

// parsing, parse number from a string
console.log(Number.parseInt('   30px', 10));
console.log(Number.parseFloat('   2.5rem'));

console.log(Number.isNaN(20));
console.log(Number.isNaN('20'));
console.log(Number.isNaN(+'20X'));
console.log(Number.isNaN(23 / 0));

// isFinite method should be used to check if any value is a number
console.log(Number.isFinite(20));

// math functions
console.log(Math.sqrt(25) === 25 ** (1 / 2));

// random integer

console.log(Math.trunc(Math.random() * 6) + 1);

const randomInt = (min, max) =>
  Math.floor(Math.random() * (max - min) + 1) + min;

console.log(randomInt(-10, 20));

// rounding integers

console.log(Math.round(23.3));
console.log(Math.round(23.3));

console.log(Math.ceil(23.3));
console.log(Math.ceil(23.3));

console.log(Math.floor(23.3));
console.log(Math.floor(23.3));

console.log(Math.trunc(-23.3));
// floor gets absolute value
console.log(Math.floor(-23.3));

// remainder

console.log(5 % 2);
console.log(8 % 2);

// even - odd f(x)

const isEven = n => n % 2 === 0;

console.log(isEven(8));
console.log(isEven(25));
console.log(isEven(514));

labelBalance.addEventListener('click', function () {
  [...document.querySelectorAll('.movements__row')].forEach(function (row, i) {
    if (i % 2 === 0) row.style.backgroundColor = 'orangered';
    if (i % 3 === 0) row.style.backgroundColor = 'blue';
  });
});

// numeric separators

// 287,460,000,000 dia of solar system
const diameter = 287_460_000_000;
console.log(diameter);

const price = 345_99;
console.log(price);

const transferFee = 15_00;
const transferFee2 = 1_500;

const PI = 3.14_15; // pointless
console.log(PI);

console.log(Number('23000'));
console.log(Number('23_000')); // NaN

// BigInt

const biggestNumInJS = 2 ** 53 - 1;
console.log(2 ** 53 - 1); // 9007199254740991
console.log(2 ** 53 + 2); // 9007199254740994 // won't calculate!
console.log(biggestNumInJS);

console.log(Number.MAX_SAFE_INTEGER);

// n will make it Big Int
console.log(12345678191202839102931341n);
console.log(BigInt(12345678191202839102931341));

// Operations
console.log(10000n + 10000n);
console.log(10000n + 10000n);

const huge = 12344567889012334556n;
const num = 22;
// won't work
// console.log(huge * num);

// will work
console.log(huge * BigInt(num));

// exceptions

console.log(20n > 13);
console.log(20n === 20); // false, === doesn't do type coercion
console.log(typeof 20n);
console.log(20n == '20');

console.log(huge + ' is REALLY big');

// divisions

console.log(11n / 3n); // cutoff decimal

// dates

// create a date 
const now = new Date();
console.log(now);
console.log(new Date('Jul 07 2023 13:22:25'));
console.log(new Date('December 24, 2015'));

console.log(new Date(account1.movementsDates[0]));

console.log(new Date(2037, 10, 19, 15, 23, 5));
console.log(new Date(2037, 10, 31)); // auto correct Dec 01

console.log(new Date(0));

// working with dates

const future = new Date(2037, 10, 19, 15, 23, 5);
console.log(future);
console.log(future.getFullYear());
console.log(future.getMonth());
console.log(future.getDay());
console.log(future.getHours());
console.log(future.getMinutes());
console.log(future.getSeconds());
console.log(future.toISOString());
console.log(future.getTime());

console.log(new Date(2142285785000));

console.log(Date.now()); // timestamp