from.js

/**
 * The Array.from() static method creates a new, shallow-copied Array instance from an array-like or iterable object.
 */

const log = console.log

// Array from a String
log(Array.from('foo'))
// [ "f", "o", "o" ]

// Array from a Set
const set = new Set(['foo', 'bar', 'baz', 'foo'])
log(Array.from(set))
// [ "foo", "bar", "baz" ]

// Array from a Map
const map = new Map([
  [1, 2],
  [2, 4],
  [4, 8],
])
log(Array.from(map))
// [[1, 2], [2, 4], [4, 8]]

const mapper = new Map([
  ['1', 'a'],
  ['2', 'b'],
])
log(Array.from(mapper.values()))
// ['a', 'b'];

log(Array.from(mapper.keys()))
// ['1', '2'];

// Array from an Array-like object (arguments)
function f() {
  return Array.from(arguments)
}
log(f(1, 2, 3))
// [ 1, 2, 3 ]

// Using arrow functions and Array.from()

// Using an arrow function as the map function to
// manipulate the elements
log(Array.from([1, 2, 3], (x) => x + x))
// [2, 4, 6]

// Generate a sequence of numbers
// Since the array is initialized with `undefined` on each position,
// the value of `v` below will be `undefined`
log(Array.from({ length: 5 }, (v, i) => i))
// [0, 1, 2, 3, 4]

// Sequence generator (range)
// Sequence generator function (commonly referred to as "range", e.g. Clojure, PHP etc)
const range = (start, stop, step) =>
  Array.from({ length: (stop - start) / step + 1 }, (_, i) => start + i * step)

// Generate numbers range 0..4
log(range(0, 4, 1))
// [0, 1, 2, 3, 4]

// Generate numbers range 1..10 with step of 2
log(range(1, 10, 2))
// [1, 3, 5, 7, 9]

// Generate the alphabet using Array.from making use of it being ordered as a sequence
log(
  range('A'.charCodeAt(0), 'Z'.charCodeAt(0), 1).map((x) =>
    String.fromCharCode(x)
  )
)
// ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"]

//fill array with 0
log(Array.from({ length: 3 }, () => 0))


const json = {
  name: "rama"
}

log(Array.from(JSON.stringify(json)))


function squared(max){
  return {
    [Symbol.iterator](){
      let n =0;
      return {
        next(){
          n++
          if(n<=max){
            return {
              value:n*n,
              done:false
            }
          }else{
            return {
              value:undefined,
              done:true
            }
          }
        }
      }
    }
  }
}

log(Array.from(squared(10)))