some js tricks you probably did not know.js

// 1. quick convert Number to String
const age = 18 + ""

console.log(typeof age) // string

// 3. fill arrays

const users = Array(5).fill('')

console.log(users); // [ '', '', '', '', '' ]

// 3. unique values out of an array

const values = ['Ed', 'daddy', 'Anna', 'tech lead', 'Anna', 'John Dough']

const unique = Array.from(new Set(values)) 

console.log(unique); // [ 'Ed', 'daddy', 'Anna', 'tech lead', 'John Dough' ]

// 4. dynamic objects properties
const dynamic = 'hobbies'

const user = {
  name: 'Ed',
  email: '[email protected]',
  [dynamic]: 'reading'
}

console.log(user); // { name: 'Ed', email: '[email protected]', hobbies: 'reading' }

// 5. slicing an array

const folks = [1, 2, 3, 4, 5]

folks.length = 3

console.log(folks); // [ 1, 2, 3 ]

// 6. slicing arrays from the end

const folksTwo = [1, 2, 3, 4, 5]


console.log(folksTwo.slice(-2)); // [ 4, 5 ]

// 7. Array to object

const folksThree = [1, 2, 3, 4, 5]

const folksObject = { ...folksThree }

console.log(folksObject); // { '0': 1, '1': 2, '2': 3, '3': 4, '4': 5 }

// 8. Object ot array

const userObjectAgain = {
  name: 'Ed',
  email: '[email protected]',
  hobbie: 'reading'
}

const userAgain = Object.values(userObjectAgain)

console.log(userAgain); // [ 'Ed', '[email protected]', 'reading' ]

// 9. performance (execution time)

let startAt = performance.now()

for (let i = 0; i < 200000; i++) {
  console.log(i)
}

let endAt = performance.now()

console.log(`${endAt - startAt} took milliseconds to execute`)