用 responseStatus 属性:
const observer = new PerformanceObserver((list) => {
list.getEntries().forEach((entry) => {
if (entry.responseStatus === 304) {
console.log(`${entry.name} was loaded from cache`);
}
});
});
observer.observe({ type: "resource", buffered: true });
或者用 transferSize 属性可以用来检查本地缓存有没有命中,如果 transferSize 的值为 0,就表示资源是从缓存加载的,不是从网络加载的