听取浏览器回流事件 [英] Listening browser reflow event

问题描述

我正在尝试收听浏览器 reflow-events 了解代码的哪些部分是最昂贵的代码。当必须（重新）绘制到屏幕上时，例如当将新元素添加到DOM时，会发生回流。

I'm trying to listen browsers reflow-events to get an idea what parts of a code are the most expensive ones. Reflow occurs when something must be (re)drawn to screen, for example when new element is added to DOM.

有没有办法在/中使用Javascript来监听这些事件，以便进一步分析？

Is there a way to listen thease events for example in/with Javascript, for further analysis?

推荐答案

我认为解决方案是使用DOM MutationObserver类。
正如文档所指出的那样：

I think the solution it's to use the DOM MutationObserver class. As the Docs point out:

它被设计为DOM3 Events规范中定义的Mutation Events的替代品。
Api Docs

该网站上的示例非常自我解释

The example on the site is pretty self explanatory

// select the target node
var target = document.querySelector('#some-id');

// create an observer instance
var observer = new MutationObserver(function(mutations) {
  mutations.forEach(function(mutation) {
    console.log(mutation.type);
  });    
});

// configuration of the observer:
var config = { attributes: true, childList: true, characterData: true };

// pass in the target node, as well as the observer options
observer.observe(target, config);

// later, you can stop observing
observer.disconnect();

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