angular - 检测页面是否第一次加载组件 Angular 6

Question

您好，有什么方法可以检测组件是否第一次以 Angular 6 加载我只想在第一次加载组件时运行函数调用，否则显示旧变量数据

Answer 1

您可以为此利用 sessionStorage 或 localStorage。

像这样:

ngOnInit() {
  if (sessionStorage.getItem('yourComponentNameLoadedAlready')) {
    // branch that this component has already been loaded
  } else { 
    // branch that this component is loading for the first time, set the session storage key to 'yes' to tell you this component has already loaded.
    sessionStorage.setItem('yourComponentNameLoadedAlready', 'yes');
   // continue doing what you want to do for first time load.
  }
}

https://developer.mozilla.org/en-US/docs/Web/API/Window/sessionStorage

localStorage 具有类似的 API，但其存储更为永久。