Tips & Trik Javascript


Perulangan String

// Long version
let str1 = ""
for(let i=0;i<5;i++){
    str1 += "Halo"
}
console.log(str1)

// Short Version
const str2 = "Halo".repeat(5)
console.log(str2)
HaloHaloHaloHaloHalo
HaloHaloHaloHaloHalo

Menggabungkan 2 Array menjadi 1

// Long version
const array1 = [20,30]
const array2 = array1.concat([40,50])
console.log(array2)

// Short Version
const array3 = [...array1,40,50]
console.log(array3)
[ 20, 30, 40, 50 ]
[ 20, 30, 40, 50 ]

Menghilangkan Duplikat Data Array

const array = [1,2,3,4,5,5,6,7,8,8,9]
const uniqueArray = [... new Set(array)]

console.log(uniqueArray)
[
  1, 2, 3, 4, 5,
  6, 7, 8, 9
]

Mengambil Nilai Maximum dan Minimum angka pada Array

const array = [2,20,7,15]

console.log('Min',Math.min(...array))
console.log('Max',Math.max(...array))
Min 2
Max 20

Perpangkatan

// Long version
var pangkat = Math.pow(4,3)
console.log(pangkat)

// Short version
var pangkat = 4 ** 3
console.log(pangkat)
64
64

Mengubah String menjadi Number

const angkaString = "21.23"
const angkaNumber = +"21.23"

console.log('angkaString',typeof angkaString)
console.log('angkaNumber',typeof angkaNumber)
angkaString string
angkaNumber number

Menghapus Nilai false dan null pada Array

const array = [13,null,20,1,false]
const filtered = array.filter(Boolean)

console.log(filtered)
[ 13, 20, 1 ]

Memberikan Nilai ke banyak variabel

// Long version
var a,b,c;
a = 1
b = 2
c = 3
console.log(a,b,c)

// Short version
var [d,e,f] = [4,5,6]
console.log(d,e,f)
1 2 3
4 5 6

Menukar value kedua variabel

let x = "Halo",y = 22;

[x,y] = [y,x];

console.log(x,y)
22 Halo

Multiple OR check

let condition = "tes"

// Long version
if(condition === "coba" || condition === "tes" || condition === 1 || condition === 10){
    console.log('OKE')
}


// Short version
if(["coba","tes",1,10].includes(condition)){
    console.log('OKE')
}

if(["coba","aja",1,10].includes(condition)){
    console.log('Tidak muncul')
}
OKE
OKE

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