JS Polyfill

I was just trying to do a simple loop over a list of elements in JS

var inputs = document.getElementsByTagName('input');
inputs.forEach(function(input, index) {
    // ...
});

but suprisingly to me I got an error:

VM52:1 Uncaught TypeError: inputs.forEach is not a function
    at <anonymous>:1:8

inputs is an HTMLCollection, which is array-like object so it should be iterable— right?

Well it is— but in modern browsers, you need to use a for loop:

for (const i of inputs) {
  // ...
}

Alternatively you can convert it to an Array with Array.from().

• Read more here

This SO answer made me curious what a “polyfill” was so I looked it up.