Differences from arrays in JavaScript
Although pseudo-arrays are similar to arrays,
they are still ordinary objects. They don't
have array methods
like map, join, slice.
For example, if you try to use slice
to DOM elements, then it just won't work:
console.log(elems.slice(1, 3)); // there will be an error
Paragraphs are given:
let elems = document.querySelectorAll('p');
Check if the array methods will work
for the variable elems.