// Flatten Arrays In Javascript 4 or 5 Ways
// Nested Array, Loop and Flatten, Array to String
// https://code-boxx.com/flatten-arrays-javascript/
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/flat
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/flatMap
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/toString
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/join
// https://www.digitalocean.com/community/tutorials/js-flat-flatmap
// TE: jaf;03 

// (A) NESTED ARRAY
var arr = [
  "First",
  ["Second", ["Third"]],
  "Forth"
];
console.log(arr);

// (B) LOOP + FLATTEN
var flatten = true;
while (flatten) {
  arr = arr.flat();
  flatten = false;
  for (let i of arr) {
    if (Array.isArray(i)) {
      flatten = true;
      break;
    }
  }
}
console.log(arr);

// (B) ARRAY TO STRING
// FIRST,SECOND,THIRD,FORTH
var str = arr.toString();
console.log(str);

// (A) ARRAYS
var fruits = ["Apple", "Banana"];
var colors = ["Red", "Yellow"];

// (B) MAP ARRAYS - NOT WHAT WE WANT
// [[APPLE, RED], [BANANA, YELLOW]]
var mapA = fruits.map((fruits, index) => [fruits, colors[index]]);
console.log(mapA);

// (C) MAP AND FLATTEN
// [APPLE, RED, BANANA, YELLOW]
var mapB = fruits.flatMap((fruits, index) => [fruits, colors[index]]);
console.log(mapB);