TIL: Ignore Right-click Events in a `mousedown` Event Handler

Making a "Print page" button. You know the drill. Use addEventListener(), pass a callback function.

document.getElementById("btnPrint").addEventListener("mousedown",printWindow);

Here's my event handler:

var printWindow = function(e) {
    window.print();
};

Once I right-clicked on the button to inspect it, I realized it would be nice to NOT open the print dialog if the user right-clicks on it for some/any reason. This would make more sense for a larger element, but whatever.

Here's my ubiquitous, ever-so-relevant Stack Overflow answer by FriendlyGuy, and the slightly more referential MDN post describing the MouseEvent.button event handler parameter.

var printWindow = function(e) {
    var isLeftMouseButton = function() { return e.button === 0; };
    if ( isLeftMouseButton() ) {
        window.print();
    }
};

Ta-da!