/**
 * for-of-loop
 * 
 * {variable} -  On each iteration a value of a different property is assigned to variable. variable may be declared with const, let, or var.
 * 
 * {iterable} Object whose iterable properties are iterated.
 */

for (variable of iterable) {
  statement
}

let testResults = [1.23, 1.10, 4.1];

for (let restResult of testResults) {
   console.log(restResult)
}

// Iterating over an array

let iterable = [10, 20, 30];

for (let value of iterable) {
  value += 1;
  console.log(value);
}
// 11
// 21
// 31

// Tip :  You can use const instead of let too, if you don't reassign the variable inside the block.

let iterable = [10, 20, 30];

for (const value of iterable) {
  console.log(value);
}
// 10
// 20
// 30

// Iterating over a String

let iterable = 'boo';

for (let value of iterable) {
  console.log(value);
}
// "b"
// "o"
// "o"

// Iterating over a TypedArray

let iterable = new Uint8Array([0x00, 0xff]);

for (let value of iterable) {
  console.log(value);
}
// 0
// 255

// Iterating over a Map

let iterable = new Map([['a', 1], ['b', 2], ['c', 3]]);

for (let entry of iterable) {
  console.log(entry);
}
// ['a', 1]
// ['b', 2]
// ['c', 3]

for (let [key, value] of iterable) {
  console.log(value);
}
// 1
// 2
// 3

// Iterating over a Set

let iterable = new Set([1, 1, 2, 2, 3, 3]);

for (let value of iterable) {
  console.log(value);
}
// 1
// 2
// 3

// Iterating over the arguments object
// You can iterate over the arguments object to examine all of the parameters passed into a JavaScript function:

(function() {
  for (let argument of arguments) {
    console.log(argument);
  }
})(1, 2, 3);

// 1
// 2
// 3

// Iterating over a DOM collection
// Iterating over DOM collections like NodeList: the following example adds a read class to paragraphs that are direct descendants of an article:

// Note: This will only work in platforms that have
// implemented NodeList.prototype[Symbol.iterator]
let articleParagraphs = document.querySelectorAll('article > p');

for (let paragraph of articleParagraphs) {
  paragraph.classList.add('read');
}

// Closing iterators
// In for...of loops, abrupt iteration termination can be caused by break, throw or return. In these cases, the iterator is closed.

function* foo(){ 
  yield 1; 
  yield 2; 
  yield 3; 
}; 

for (let o of foo()) { 
  console.log(o); 
  break; // closes iterator, execution continues outside of the loop
}
console.log('done');

// Iterating over generators
// You can also iterate over generators, i.e. functions generating an iterable object:

function* fibonacci() { // a generator function
  let [prev, curr] = [0, 1];
  while (true) {
    [prev, curr] = [curr, prev + curr];
    yield curr;
  }
}

for (let n of fibonacci()) {
  console.log(n);
  // truncate the sequence at 1000
  if (n >= 1000) {
    break;
  }
}

// Iterating over other iterable objects
// You can also iterate over an object that explicitly implements the iterable protocol:

let iterable = {
  [Symbol.iterator]() {
    return {
      i: 0,
      next() {
        if (this.i < 3) {
          return { value: this.i++, done: false };
        }
        return { value: undefined, done: true };
      }
    };
  }
};

for (let value of iterable) {
  console.log(value);
}
// 0
// 1
// 2