example-with-dependency-change-trigger-useEffect

Full code

/* eslint-disable */
import React, { useState, useEffect } from 'react';
import Plot from 'react-plotly.js';
import { Button } from "../Button";

const MyComponent = () => {
   const [yValue, setYValue] = useState(6);
   const [isIncrementing, setIsIncrementing] = useState(true);

   useEffect(() => {
      let interval = null;

      if (isIncrementing) {
         interval = setInterval(() => {
            setYValue((prevYValue) => prevYValue + 1);
         }, 1000);
      } else if (!isIncrementing && interval) {
         clearInterval(interval);
      }

      return () => clearInterval(interval);
      // The change to isIncrementing will trigger this effect to run again
   }, [isIncrementing]);

   const buttonText = isIncrementing ? 'Stop Incrementing' : 'Start Incrementing';

   function handleButtonClick() {
      setIsIncrementing((prevIsIncrementing) => !prevIsIncrementing);
   }

   return (
      <>
         <Plot
            data={[
               {
                  x: [1, 2, 3],
                  y: [2, yValue, 3],
                  type: 'scatter',
                  mode: 'lines+markers',
                  marker: {color: 'red'},
               },
               {type: 'bar', x: [1, 2, 3], y: [2, yValue, 3]},
            ]}
            layout={{width: 800, height: 400, title: 'A Fancy Plot'}}
         />
         <Button onClick={handleButtonClick}>{buttonText}</Button>
      </>
   );
};

export default MyComponent;

self-analyze-desktop-electron/aa6e236

   const [yValue, setYValue] = useState(6);
   const [isIncrementing, setIsIncrementing] = useState(true);

   useEffect(() => {
      let interval = null;

      if (isIncrementing) {
         interval = setInterval(() => {
            setYValue((prevYValue) => prevYValue + 1);
         }, 1000);
      } else if (!isIncrementing && interval) {
         clearInterval(interval);
      }

      return () => clearInterval(interval);
      // The change to isIncrementing will trigger this effect to run again
   }, [isIncrementing]);

   const buttonText = isIncrementing ? 'Stop Incrementing' : 'Start Incrementing';

   function handleButtonClick() {
      setIsIncrementing((prevIsIncrementing) => !prevIsIncrementing);
   }

In the above code, I added a isIncrementing state variable that is set to true when the component mounts. The useEffect hook checks if isIncrementing is true before setting up the interval, and if it's false, it will clear the interval.

I also added the isIncrementing variable to the dependency array of the useEffect hook. This means the effect will run every time isIncrementing changes, starting the interval when it becomes true, and clearing it when it becomes false.

In the handleButtonClick function, I toggle the value of isIncrementing to start or stop the interval when the button is clicked.

The buttonText variable is used to change the text of the button based on whether the interval is running or not.

This way, we don't need to extract a separate Incrementor class and can achieve the desired functionality in a simpler way, taking full advantage of React's built-in hooks and state management. #chatgpt4

Backlinks

useEffect