在 render() 之前使用什么组件生命周期来做某事? [英] What component lifecycle to use to do something before render()?

问题描述

我需要检查一些道具(来自 redux 商店)是否为空对象.如果它是空的，我希望页面重定向到另一个页面而不是调用 render().

I need to check whether some props (from redux store) is an empty object or not. If it is empty, I want the page to redirect to another page and not bother to call render().

目前的流程是这样的:

constructor(props) {
   this.checkObject();
}

checkObject() {
  if (Object.keys(someObj).length === 0 && someObj.constructor === Object) {
    this.props.history.push("/some-other-route");
  }
}

render() {
   // some code
}

但是，当我执行 console.log 时，在 checkObject() 之后调用 render() 这会导致一些错误，因为 render() 需要一个非空对象才能正确显示内容.这就是为什么如果对象为空(我通过 checkObject() 检查)，我什至不想调用 render() 并且只是重定向到另一个页面的原因.

However, when I do a console.log, render() is being called after checkObject() which causes some errors because render() needs a non-empty object to display content properly. That's the reason I don't want react to even call render() if the object is empty (which I check through checkObject()) and just redirect to another page.

那么是否有生命周期方法可以在调用 render() 之前执行我的重定向代码?

So is there a lifecycle method to use that will execute my redirection code before render() is called?

推荐答案

你可以在 render 中使用 react-router 的 Redirect 组件.

You could use the Redirect component of react-router within render.

import { Redirect } from 'react-router'
render(){

 (checkIfObjectEmpty)?<Redirect to = '/some_route'/>:<JSX>

}

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