观察 Vuejs 中 window.scrollY 的变化 [英] Watch window.scrollY changes in Vuejs

问题描述

我有一个非常简单的应用程序，它有 2 个组件:App.vue 和另一个组件 Home.vue，我在其中保存了其余的结构应用程序:一个粘性标题和一些带有可滚动到的锚点的部分.

我想对粘性标题应用一个类，以在滚动页面时最小化徽标.所以我想我会注意 window.scrollY 中的任何变化.因此，如果 scrollY 大于 0，则应用一些最小化徽标的类.

我尝试在我的组件中监听滚动事件，但这并没有走多远.在这里的这个讨论中，提供了一个非常好的解决方案，但我不知道在哪里放置滚动事件.

I have a very simple app, that has 2 components: the App.vue and another component, Home.vue where I hold the rest of the structure of the app: a sticky header and some sections with anchors to scroll to.

I want to apply a class to the sticky header to minimize the logo while the page is scrolled. So I thought I'd watch for any changes in window.scrollY. So if scrollY is greater than 0, apply some class that minimizes the logo.

I tried to listen to scroll events in my component, but that didn't go very far. In this discussion here, a very good solution is provided, but I don't know where to place the scroll event. https://github.com/vuejs/Discussion/issues/324

So, I thought the most fitting solution would be to create a data property, assign it the window.scrollY figure and then watch for changes in its value. Unfortunately, the watcher is never triggered. So now I'm stuck. The code is:

data () {
return {
  ...
  windowTop: window.top.scrollY
 }
}
...
watch: {
 windowTop: {
  immediate: true,
  handler (newVal, oldVal) {
    console.log(newVal, oldVal);
  },
 }
}

Any ideas of what I might be doing wrong?

解决方案

window properties can't be used reactively like that. Instead, you'd have to listen to the window's scroll event and respond accordingly:

mounted() {
  window.addEventListener("scroll", this.onScroll)
},
beforeDestroy() {
  window.removeEventListener("scroll", this.onScroll)
},
methods: {
  onScroll(e) {
    this.windowTop = window.top.scrollY /* or: e.target.documentElement.scrollTop */
  }
}

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