ReactJS - 事件未定义，它不会呈现 onChange 事件？

Question

I'm trying to create a converter from inches to cm and feet to cm but I want to have only one input and to switch between them with buttons. I created a value this.bol set to neutral and some click events to change that value. Depending on that value the onChange event will listen and know which state to update but I get events is not defined.

Answer 1

It is because you call the function without passing the event. The callback function you pass to onChange gets the event as first parameter and you have to manually pass it to you custom handler.

<input onChange={(event) => {
  return this.handler(event);
}}>