Solutions for the Plain Concepts JavaScript Quizz! ⚡

plain_concepts.js

// ej1
const list = [1,2,3,4,5,6,7]
const result = list
  .forEach(a => a % 2 === 0 ? a : -a)
  .filter(b => b > 2)
  .some(c => c < 10)
console.log('ej1', result) // throws an error, because of `forEach`

// ej2
const key = Symbol("${window}")
const inmutable = {
  [key]: 'Hello'
}
inmutable[key] = `${'world'}`
console.log('ej2', inmutable[key]) // > 'world'

// ej3
function* hello() {
  yield 'hello'
  return 'world'
  yield 'hello world'
}
const gen = hello()
gen.next()
gen.next()
console.log('ej3', gen.next()) // > undefined (because it never reaches the second yield)

// ej4
let arr = []
for (let i = 0; i < 3; ++i) {
  arr.push(i.toString() + (i & 0))
}
console.log('ej4', arr) // > ['00', '10', '20']