Arrays.js

const boxes = document.querySelectorAll('.box');

//ES5
// change to dodgerblue color all the boxes
var boxesArr5 = Array.prototype.slice.call(boxes);
boxesArr5.forEach(function (cur) {
    cur.style.backgroundColor = 'dodgerblue';
});

//ES6
// change to dodgerblue color all the boxes
const boxesArr6 = Array.from(boxes);
Array.from(boxes).forEach(cur => cur.style.backgroundColor = 'dodgerblue');

//ES5
// changing boxes text content
for (var i = 0; i < boxesArr5.length; i++) {

    if (boxesArr5[i].className === 'box blue') {
        continue;
    }

    boxesArr5[i].textContent = 'I changed to blue!';

}


//ES6
// changing boxes text content
for (const cur of boxesArr6) {
    if (cur.className.includes('blue')) {
        continue;
    }
    cur.textContent = 'I changed to blue!';
}



//ES5
var ages = [12, 17, 8, 21, 14, 11];

var full = ages.map(function (cur) {
    return cur >= 18;
});

console.log(full); // [false, false, false, true, false, false]
console.log(full.indexOf(true)); // 3
console.log(ages[full.indexOf(true)]); // 21


//ES6
console.log(ages.findIndex(cur => cur >= 18)); // 3
console.log(ages.find(cur => cur >= 18)); // 21