如何在 React 中将整数值从父道具传递给子道具

Question

Basically I am working on a dice game where I have a class for Number of sides and another class for Number of dices. I want to get values from both classes and pass them to a child class where I will multiply both together to get maxScore . All classes are in same file

However, I get NaN as a result. I feel like I am not passing values correctly. All classes are in same file. I am new to React so any help would be appreciated.

Answer 1

In both cases you are missing out one of the props values. So the component tries to multiply undefined with a number and that's why you are getting NaN .

Think about the following:

 console.log(6 * undefined); console.log(undefined * 2);

As a solution you need to provide both values for <Child> component. Try the following:

<Child noOfSides={this.state.mystate} noOfDice={1} />

{/* or */}

<Child noOfDice={this.state.mystate} noOfSides={1}/> 

I hope this explains!