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                <div class="item item-1">I am an item.</div>
<div class="item item-2">I am an item.</div>
<div class="item item-3">I am an item.</div>
<div class="item item-4">I am an item.</div>
<div class="item item-5">I am an item.</div>


                body {
  display: flex;

.item {
  padding: 1rem;
  margin: 1rem 0 1rem 1rem;
  border: 1px solid #ccc;
  max-width: 10rem;
  box-shadow: 2px 5px 20px rgba(black, 0.07);
  border-radius: 0.2rem;



// first select all of the items..
const items = document.getElementsByClassName('item');
// At this point, items = a HTMLCollection with 5 items
// HTMLCollection(5) [div.item,div.item,div.item,div.item,div.item ]

// Using the new spread operator, we can transform this HTMLCollection
// into an array, which gives us access to a bunch of useful methods
const itemsArray = [...items];
// itemsArray now = a array(5) [div.item, div.item, div.item, div.item, div.item]

// now we have an array we can easily use over them using forEach
itemsArray.forEach((item, index) => {
    // each of items is an 'Element', which gives you access to a bunch
    // of object methods
    // also, you can access the index of the loop

but we can make this one step shorter!
Also if you don't need the index, feel free to omit it
note we already defined const items above
[...items].forEach(item => console.log(item));

or if you were feeling really wild...
this is potentially less performant, if there's any chance
you'll be running this loop more than once, you'll definately
want to store the HTMLCollection in memory first, but that's up to you
[...document.getElementsByClassName('item')].forEach(item => console.log(item));

Array.from(items).forEach(item => console.log(item));