Showing Greeting Message using ReactJS

In ReactJS, To Display Personalized Greeting message (like “Good Morning”, “Good Afternoon” ) based on the current time, we need to follow the following code.

import React, { useEffect, useState } from 'react';
import { Typography } from '@mui/material';

const Greeting = ({ user }) => {
    const [greeting, setGreeting] = useState('');
    const [color, setColor] = useState('');

    const updateGreeting = () => {
        const hour = new Date().getHours();

        if (hour < 12) {
            setGreeting('Good Morning');
            setColor('#FFA726');
        } else if (hour < 17) {
            setGreeting('Good Afternoon');
            setColor('#29B6F6');
        } else if (hour < 20) {
            setGreeting('Good Evening');
            setColor('#9AB7BC');
        } else {
            setGreeting('Good Night');
            setColor('#0FFDE4');
        }
    };

    useEffect(() => {
        updateGreeting();
        const interval = setInterval(updateGreeting, 60 * 1000);
        return () => clearInterval(interval);
    }, []);

    return (
        <Typography variant="h6">
            <span style={{ color, fontWeight: 500 }}>{greeting}</span>{' '}
            <span>{user.name || user.role}</span>
        </Typography>
    );
};

export default Greeting;

const [greeting, setGreeting] = useState(”) ==> This holds the current Greeting string (like “Good Morning”, “Good Afternoon” ).

const [color, setColor] = useState(”) ==> This holds the current color for the Greeting Text.

const hour = new Date().getHours() ==> Gives current hour. Based on the current hour, it will compare with 12, 17, 20 and sets different greeting message and associated color.

useEffect() ==> For the first render calls updateGreeting(), and displays the Greeting message. Then we used setInterval(updateGreeting, 60 * 1000), to update the Greeting message for every 1 minute. Finally this line return () => clearInterval(interval), cleans up the interval when the component unmounts to prevent the memory leaks.