function getPropertyValue(element, propertyName, fn, skipCache) {
    var data = Data(element);
    var propertyValue = void 0;
    if (NoCacheNormalizations.has(propertyName)) {
        skipCache = true;
    }
    if (!skipCache && data && data.cache[propertyName] != null) {
        propertyValue = data.cache[propertyName];
    } else {
        fn = fn || getNormalization(element, propertyName);
        if (fn) {
            propertyValue = fn(element);
            if (data) {
                data.cache[propertyName] = propertyValue;
            }
        }
    }
    if (Velocity$$1.debug >= 2) {
        console.info("Get \"" + propertyName + "\": \"" + propertyValue + "\"", element);
    }
    return propertyValue;
}
Get a property value. This will grab via the cache if it exists, then
via any normalisations.