如何通过 React-slick useRef hook 和 typescript 使用 AutoPlay 方法

Question

I'm currently using "typescript": "^3.7.5" and "react-slick": "^0.25.2" .

The problem I am facing is that I'm not able to use the auto play methods slickPlay and slickPause with the new useRef hook and typescript.

Goal: To be able to pause auto play and resume auto play with a play/pause button. My play/pause button will be next to the pagination dots.

My Code:

import React, { useStateuseRef } from 'react';

const myComponent = () => {
  const [autoPlayOn, setAutoPlayOn] = useState<boolean>(true);
  const sliderRef = useRef<typeof Slider | null>(null);
  
  <Slider
    ref={sliderRef}
    appendDots={(dots): JSX.Element => (
      <MyButton
        onClick={() => {
          setAutoPlayOn(!autoPlayOn);
          if (autoPlayOn) {
            sliderRef.slickPlay();
          } else {
            sliderRef.slickPause();
          }
        }}
      />
    )}
    {...otherSettings}
  >
}

The type error that I am getting is:

No overload matches this call.
  Overload 1 of 2, '(props: Readonly<Settings>): Slider', gave the following error.
    Type 'MutableRefObject<typeof Slider | null>' is not assignable to type 'string | ((instance: Slider | null) => void) | RefObject<Slider> | null | undefined'.
      Type 'MutableRefObject<typeof Slider | null>' is not assignable to type 'RefObject<Slider>'.
        Types of property 'current' are incompatible.
          Type 'typeof Slider | null' is not assignable to type 'Slider | null'.
            Type 'typeof Slider' is missing the following properties from type 'Slider': slickNext, slickPause, slickPlay, slickPrev, and 8 more.
  Overload 2 of 2, '(props: Settings, context?: any): Slider', gave the following error.
    Type 'MutableRefObject<typeof Slider | null>' is not assignable to type 'string | ((instance: Slider | null) => void) | RefObject<Slider> | null | undefined'.
      Type 'MutableRefObject<typeof Slider | null>' is not assignable to type 'RefObject<Slider>'.

I'm also getting another error when clicking on the button: TypeError: sliderRef.slickPlay is not a function

I'm attempting to call the slick methods slickPlay and slickPause , however I'm running into type errors. I've looked at the examples https://github.com/akiran/react-slick/blob/master/examples/AutoPlayMethods.js however I'm not able to achieve the desired result still.

It confuses me to use these methods for functional components instead of class-based components. Adding in the layer of typescript makes it that much more challenging.

Thank you in advance.

Answer 1

I'll address the second part first: when using useRef , you have to refer to .current to get the actual instance. So, your calls would look like:

sliderRef.current.slickPlay();

Now the first part. This one, I'm willing to believe that this could change depending on which version of Typescript/React/react-slick you're using, but for me, Typescript stops complaining if I just use:

const sliderRef = React.useRef<Slider>(null);

Answer 2

I was able to get this to work by making a check on .current instead of sliderRef .

const sliderElement = sliderRef.current;

if (sliderElement) {
  // do stuff
}

This small nuance was able to pass the type errors.

For the useRef declaration, this line worked(thanks to help from @jnpdx)

const sliderRef = React.useRef<Slider | null>(null);