Function whichButtons

docs/app/js/sanddance-app.js:95182–95209

(event)

const MOUSE_EVENT_BUTTONS_RIGHT_MASK = 2;
const MOUSE_EVENT_BUTTONS_MIDDLE_MASK = 4;
function whichButtons(event) {
    const eventType = MOUSE_EVENTS[event.srcEvent.type];
    if (!eventType) // Not a mouse evet
    return null;
    const { buttons , button , which  } = event.srcEvent;
    let leftButton = false;
    let middleButton = false;
    let rightButton = false;
    if (// button is up, need to find out which one was pressed before
    eventType === UP_EVENT || eventType === MOVE_EVENT && !Number.isFinite(buttons)) {
        leftButton = which === MOUSE_EVENT_WHICH_LEFT;
        middleButton = which === MOUSE_EVENT_WHICH_MIDDLE;
        rightButton = which === MOUSE_EVENT_WHICH_RIGHT;
    } else if (eventType === MOVE_EVENT) {
        leftButton = Boolean(buttons & MOUSE_EVENT_BUTTONS_LEFT_MASK);
        middleButton = Boolean(buttons & MOUSE_EVENT_BUTTONS_MIDDLE_MASK);
        rightButton = Boolean(buttons & MOUSE_EVENT_BUTTONS_RIGHT_MASK);
    } else if (eventType === DOWN_EVENT) {
        leftButton = button === MOUSE_EVENT_BUTTON_LEFT;
        middleButton = button === MOUSE_EVENT_BUTTON_MIDDLE;
        rightButton = button === MOUSE_EVENT_BUTTON_RIGHT;
    }
    return {
        leftButton,
        middleButton,
        rightButton
    };
}
function getOffsetPosition(event, rootElement) {
    const center = event.center;
    // `center` is a hammer.js event property