我们正在使用TTVC来衡量网络上的性能--现在你也可以了。

Nobody likes waiting for software. Snappy, responsive interfaces make us happy, and research shows there’s a relationship between responsiveness and attention1. But maintaining fast-feeling websites often requires tradeoffs. This might mean diverting resources from the development of new features, paying off technical debt, or other engineering work. The key to justifying such diversions is by connecting the dots between performance and business outcomes—something we can do through measurement.

没有人喜欢等待软件。快速响应的界面让我们感到高兴，研究表明响应性和注意力之间有一定的关系1。但维持快速感觉的网站往往需要权衡利弊。这可能意味着要从新功能的开发中转移资源，偿还技术债务或其他工程工作。要证明这种转移的合理性，关键是要把性能和业务成果联系起来--这一点我们可以通过测量来做到。

Over the last year, we’ve been rethinking the way we track page load performance on the web at Dropbox. After identifying a few gaps in our existing metrics, we decided we needed a more objective, user-focused way to define page load performance so that we could more reliably and meaningfully compare experiences across products. We thought a relatively new page load metric called Time To Visually Complete (TTVC) could work well.

在过去的一年里，我们一直在重新思考我们在Dropbox的网络上跟踪页面加载性能的方式。在确定了我们现有指标中的一些差距后，我们决定需要一种更客观、以用户为中心的方式来定义页面加载性能，以便我们能够更可靠和有意义地比较不同产品的体验。我们认为一个相对较新的页面加载指标，即视觉完成时间（TTVC）可以很好地发挥作用。

There was just one problem: Browsers don’t yet report the moment a page becomes visually complete. If we wanted to adopt TTVC as our new primary performance metric, we would have to fill that gap. So we built a small library to allow us to track TTVC as our users experience it in the real world. That library is @dropbox/ttvc—and we’re excited to be open-sourcing this work!

只有一个问题：浏览器还没有报告一个页面在视觉上变得完整的时刻。如果我们想采用TTVC作为我们新的主要性能指标，我们就必须填补这一空白。因此，我们建立了一个小型库，使我们能够跟踪TTVC，因为我们的用户在现实世界中体验到它。这个库就是@dropbox/ttvc--我们很高兴能将这项工作开源。

Some common pageload performance metrics

一些常见的页游性能指标

When monitoring a page load, there are several useful milestones (Google’s Web Vitals project has recently popularized a few). Each of these metrics are measured from the moment the browser first issues a new request:

在监测页面加载时，有几个有用的里程碑（谷...