Can i call a specific function inside `useEffect` in React? - reactjs

Question

I have a canvas component in react. I am using useEffect to get the canvas element. So i have defined all needed functions in useEffect, as you can see below
import { useEffect, useRef } from "react"
import * as blobs2Animate from "blobs/v2/animate"
export const CornerExpand = () => {
const canvasRef = useRef<HTMLCanvasElement>(null)
useEffect(() => {
const canvas = canvasRef.current!
const ctx = canvas.getContext("2d")
const animation = blobs2Animate.canvasPath()
const width = canvas.clientWidth * window.devicePixelRatio
const height = canvas.clientHeight * window.devicePixelRatio
canvas.width = width
canvas.height = height
const renderAnimation = () => {
if (!ctx) return
ctx.clearRect(0, 0, width, height)
ctx.fillStyle = "#E0F2FE"
ctx.fill(animation.renderFrame())
requestAnimationFrame(renderAnimation)
}
requestAnimationFrame(renderAnimation)
const size = Math.min(width, height) * 1
const defaultOptions = () => ({
blobOptions: {
seed: Math.random(),
extraPoints: 36,
randomness: 0.7,
size,
},
canvasOptions: {
offsetX: -size / 2.2,
offsetY: -size / 2.2,
},
})
const loopAnimation = () => {
animation.transition({
duration: 4000,
timingFunction: "ease",
callback: loopAnimation,
...defaultOptions(),
})
}
animation.transition({
duration: 0,
callback: loopAnimation,
...defaultOptions(),
})
const fullscreen = () => {
const options = defaultOptions()
options.blobOptions.size = Math.max(width, height) * 1.6
options.blobOptions.randomness = 1.4
options.canvasOptions.offsetX = -size / 2
options.canvasOptions.offsetY = -size / 2
animation.transition({
duration: 2000,
timingFunction: "elasticEnd0",
...options,
})
}
}, [canvasRef])
return (
<div>
<canvas className="absolute top-0 left-0 h-full w-full" ref={canvasRef} />
</div>
)
}
export default CornerExpand
Everything works as well, but now I have a problem. I want to execute the fullscreen() function when a button is clicked in the parent component. Since I have defined the function in useEffect, I can't call it directly, isn't it? What can I do to solve this?

Answer 1

You can do it like this.
export const CornerExpand = React.forwardRef((props, ref) => {
//....
{
//...
const fullscreen = () => {
const options = defaultOptions()
options.blobOptions.size = Math.max(width, height) * 1.6
options.blobOptions.randomness = 1.4
options.canvasOptions.offsetX = -size / 2
options.canvasOptions.offsetY = -size / 2
animation.transition({
duration: 2000,
timingFunction: "elasticEnd0",
...options,
})
}
ref.current = fullscreen;
}, [canvasRef]);
You can wrap this comp with React.forwardRef. And call it from parent.
<CornerExpand ref={fullscreenCallbackRef} />
And then call like this
fullscreenCallbackRef.current()