[1,2,3].push(4) //[1,2,3,4]

[1,2,3].pop() // [1,2]

[1,2,3].shift() // [2,3]

[1,2,3].unshift(0) // [0,1,2,3]

['a', 'b'].concat('c') // ['a', 'b', 'c']

const first = [1, 2, 3]
const second = [4, 5, 6]

const concatedArr = first.concat(second) // [1, 2, 3, 4, 5, 6]

['a', 'b', 'c'].join('-') // a-b-c

[10, 20, 30, 40, 50].slice(1,4) // [20, 30, 40]

['a', 'b', 'c'].indexOf('b') // 1

['a', 'b', 'c'].includes('c') // true
['a', 'b', 'c'].includes(1) // false

[3,5,6,8].find(n => n % 2 === 0) // 6

[5, 12, 8, 130, 44].findIndex(n => n > 13) // 3

[3,4,8,6].map((n) => n * 2) // [6,8,16,12]

[1,4,7,8].filter(n => n % 2 === 0) // [4,8]

[2,4,3,7].reduce((acc, cur) => acc + cur) // 16

[1,2,3,4].every(n => n < 5) // true

[2,4,6,8].some(n => n > 5) // true

[1,2,3,4].reverse() // [4,3,2,1]

[5, 12, 8, 130, 44].at(2) // 8

['a', 'b', 'c'].forEach(item => console.log(item)) 
// a
// b
// c

[0, 1, 2, [3, 4]].flat() // [0,1,2,3,4]

[0, 1, 2, [[[3, 4]]]].flat(2) // [0, 1, 2, [3, 4]]