javascript - ComponentDidUpdate 用法和超出最大更新深度

Question

我有一个设置屏幕，我可以在其中获取用户的信息数量，例如年龄、体重和性别，然后根据这些信息计算用户每天应该喝多少水。

我想自动计算这个金额而不需要计算按钮。

Invariant Violation: Maximum update depth exceeded. This can happen when a component repeatedly calls setState inside componentWillUpdate or componentDidUpdate. React limits the number of nested updates to prevent infinite loops.

我当前计算水量的代码

  //function to calculate how much water to drink
  waterCalculator = () => {
    //let weightPound = this.state.weight * 2.2046;
    let weightValue = this.state.weight;
    let ageValue = this.state.age;
    let waterAmount = null;
    if (ageValue < 30) {
      waterAmount = weightValue * 40;
    } else if (ageValue >= 30 || ageValue <= 55) {
      waterAmount = weightValue * 35;
    } else {
      waterAmount = weightValue * 30;
    }
    this.setState({ sliderValue: waterAmount });
  };

这就是我想要自动更新水量的方式

  //checking if age and weight and gender states are changed call the function
   componentDidUpdate(prevState) {
     if (
       this.state.age !== prevState.age &&
       this.state.weight !== prevState.weight &&
       this.state.gender !== prevState.gender
     ) {
       this.waterCalculator();
     }
   }

Answer 1

componentDidUpdate(prevState) { // <===Error

}

问题是 componentDidUpdate 中的第一个参数是 prevProps 而不是 prevState

解决问题

componentDidUpdate(prevProps, prevState) {
  ...
}

只需将 prevState 放入第二个参数