Solve the problem, then learn the tool.شوف المشكلة الأول، وبعدها اتعلم الأداة اللي هتحلها.

let x;

const num = new Number(5);

// toString() - returns a string representation of the number
x = num.toString();
// To get the length
x = num.toString().length;

// toFixed() - returns a string representation of the number with a specified number of decimals
x = num.toFixed(2);

// toPrecision() - returns a number with the specified length
x = num.toPrecision(3);

// toExponential() -  convert a number to exponential notation and return its value as a string
x = num.toExponential(2);
// toLocaleString() - returns a string representation of the number, using the current locale
x = num.toLocaleString('en-US');

// valueOf - Get value
x = num.valueOf();

// The Number object itself has some properties and methods

// Largest and smallest possible number
x = Number.MAX_VALUE;
x = Number.MIN_VALUE;

console.log(x);

let x;

// Square root
x = Math.sqrt(9);

// Absolute value
x = Math.abs(-5);

// Round
x = Math.round(4.2);

// Round up
x = Math.ceil(4.2);

// Round down
x = Math.floor(4.9);

// Exponent
x = Math.pow(2, 3);

// Minimum number
x = Math.min(4, 5, 3);

// Maximum number
x = Math.max(4, 5, 3);

// Get a random number/decimal between 0 and 1
x = Math.random();

// Get a random number between 1 and 100
x = Math.floor(Math.random() * 100 + 1);

console.log(x);

let d;

// Get today's date and time
d = new Date();

// Set to a string
d = d.toString();

// Get a specific date
// Important: the month is 0-based, so 0 is January and 11 is December
d = new Date(2021, 0, 10, 12, 30, 0);

// Pass in a string
d = new Date('2021-07-10T12:30:00');
d = new Date('07/10/2021 12:30:00');
d = new Date('2022-07-10');
d = new Date('07-10-2022');

// https://stackoverflow.com/questions/7556591/is-the-javascript-date-object-always-one-day-off
// Get current timestamp
d = Date.now();

// Get the timestamp of a specific date
d = new Date();
d = d.getTime();
d = d.valueOf();

// Create a date from a timestamp
d = new Date(1666962049745);

// Convert from milliseconds to seconds
d = Math.floor(Date.now() / 1000);

console.log(d);

let x;
let d = new Date();

// Date methods

x = d.toString();

x = d.getTime();
x = d.valueOf();

x = d.getFullYear();

x = d.getMonth();
x = d.getMonth() + 1;

x = d.getDate();

x = d.getDay();

x = d.getHours();

x = d.getMinutes();

x = d.getSeconds();

x = d.getMilliseconds();

x = `${d.getFullYear()}-${d.getMonth() + 1}-${d.getDate()}`;
// Intl.DateTimeFormat API (locale specific)
x = Intl.DateTimeFormat('en-US').format(d);
x = Intl.DateTimeFormat('en-GB').format(d);
x = Intl.DateTimeFormat('default').format(d);

x = Intl.DateTimeFormat('default', { month: 'long' }).format(d);

x = d.toLocaleString('default', { month: 'short' });

x = d.toLocaleString('default', {
  weekday: 'long',
  year: 'numeric',
  month: 'long',
  day: 'numeric',
  hour: 'numeric',
  minute: 'numeric',
  second: 'numeric',
  timeZone: 'America/New_York',
});
console.log(x);

let x;

// Array Literal
const numbers = [12, 45, 33, 29, 39, 102];
const mixed = [12, 'Hello', true, null];

// Array Constructor
const fruits = new Array('apple', 'grape', 'orange');

// Get value by index
x = numbers[0];

x = numbers[0] + numbers[3];

x = `My favorite fruit is an ${fruits[2]}`;

x = numbers.length;

fruits[2] = 'pear';

// length is not read-only
// fruits.length = 2;

fruits[3] = 'strawberry';
// Using the length as the index will always add on the the end
fruits[fruits.length] = 'blueberry';
fruits[fruits.length] = 'peach';

x = fruits;

console.log(x);

let x;

const arr = [28, 38, 44, 29, 109];

// push() - Push a value on to the end of the array
arr.push(100);

// pop() - Take the last value off
arr.pop();

// unshift() - Add a value to the beginning of the array
arr.unshift(99);

// shift() - Remove first value
arr.shift();

// reverse() - Reverse an array
arr.reverse();

// includes() - Check to see if something is in the array
x = arr.includes(445);

// indexOf() - Return the index of the first match
x = arr.indexOf(28);
// Return array as a string
x = arr.toString();
x = arr.join();

// slice() returns selected elements in an array, as a new array. Slice takes in the index of the first element and the index of the last element to be included in the new array.
x = arr.slice(1, 4);

// splice() works like slice() except it takes the index of the first element and the number of elements after that as a second argument. it also mutates the original array where slice() does not
x = arr.splice(1, 4);
// Remove a single element/value - The following will mutate the original array by taking out the element with the index of 4. x will be equal to a new array with that plucked out value.
x = arr.splice(4, 1);

// Chaining methods - Some methods can be chained depending on the return value.
x = arr.slice(1, 4).reverse().toString().charAt(0);

console.log(x);

let x;

const fruits = ['apple', 'pear', 'orange'];
const berries = ['strawberry', 'blueberry', 'rasberry'];

// Nesting arrays

// Nesting berries inside of fruits
fruits.push(berries);

// Now we can access 'blueberry' with the following
x = fruits[3][1];

// Create a new variable and nest both arrays
const allFruits = [fruits, berries];

x = allFruits[1][2];

// concat() - Concatenate arrays
x = fruits.concat(berries);

// spread operator (...) - Concatenate with
x = [...fruits, ...berries];
// flat() - Flatten an array
const arr = [1, 2, [3, 4, 5], 6, [7, 8]];
x = arr.flat();

// Static methods of Array object

// isArray() - Check is is an array
x = Array.isArray(fruits);

// from() - Create an array from an array like value
x = Array.from('12345');

// of() - Create an array from a set of values
const a = 1;
const b = 2;
const c = 3;

x = Array.of(a, b, c);

console.log(x);