Javascript forEach on empty array [].forEach.call

Question

Please can someone explain what this command does in javascript or how this language feature is called? Why is there forEach on empty array?

[].forEach.call(document.querySelectorAll('.mdc-text-field'), function (el) {
  new MDCTextField(el);
});

I am new to frontend technologies.

Please refer to this reference: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/call - The code you provide is a hack that is unecessary. It passes the first argument to `call()` to the `forEach()` method of the array. The array is empty, but the first argument contains a DOM NodeList that can act like an array. So this basically uses the `forEach()` method to iterate over the DOM elements. It isn't necessary because the DOM NodeList object has a forEach method. — Randy Casburn, Dec 13 '20 at 14:07
@RandyCasburn "*It isn't necessary because the DOM NodeList object has a forEach method*"–That code is likely legacy. `NodeList#forEach` is not supported in Internet Explorer and other older browsers. — str, Dec 13 '20 at 14:09
Here is the reference to the [DOM NodeList API](https://developer.mozilla.org/en-US/docs/Web/API/NodeList) - There you will find it has a `forEach()` method so the hack is not required. All that is needed is this: `document.querySelectorAll(...).forEach(...)` — Randy Casburn, Dec 13 '20 at 14:09
Yes, @str is correct - if this is legacy code use for IE, then there is no choice but to use this hack. — Randy Casburn, Dec 13 '20 at 14:10

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