从组件安装反应计数时间

Question

In React / Javascript, how can one count time from when the component mounted? I wish to stay on a page a minimum time of 0,8 seconds. So when component mounts, I wish to start a timer, that calculates whether the 0,8 seconds have passed. When I'm about to leave the page, I want to check whether that time has passed, and if not, then wait for the remain time, and then leave the page. How could I accomplish this?

Answer 1

React has multiple life-cycle events which one of them is componentDidMount .

componentDidMount() is invoked immediately after a component is mounted. Initialization that requires DOM nodes should go here. If you need to load data from a remote endpoint, this is a good place to instantiate the network request. Setting state in this method will trigger a re-rendering.

Example

componentDidMount() {
  this.mountTime = (new Date).getTime();
}

onSomeActionThatTriggersUnmount() {
  const currentTime = (new Date).getTime();
  if(currentTime >= (this.mountTime + 800)) {
    // proceed with the unmount
  } else {
    // not enough time yet
  }
}