If you're like myself and forget over time what some of the more uncommonly used equality operators actually do under the hood, this resource is great for getting a quick explanation of the functionality and a general level of support across browsers.
Simply type in the operator you'd like an explanation for such as the nullish-coalescing operator (??) to get an immediate result. You can also select an operator from the list under the search if you're not immediately sure which operator you're looking for.