I am trying to render each element in the roles array. This code works in the timer (setInterval) is as follows:
Assigns the duplicate value of the state in
let prevRolevariable and its corresponding index in thelet prevRoleIndexvariable.Renders the string of random characters 10 times iteratively with 50ms delay.
Now the next element in the
rolesarray is assigned tolet newRolevariable, by adding +1 topreviousRoleIndexand then updating the state with newRole variable.
import {useState, useEffect} from 'react'
const roles = ['Web Developer & UX Designer', 'Software Developer / Engineer', 'Blockchain Developer', 'Data Anaylist/ Scientist']
export default function App() {
const [role, setRole] = useState(roles[0])
const sleep = (value) =>{
return new Promise(r => setTimeout(r, value));
}
const getRandomString = () =>{
return (Math.random()).toString(36).substring(2);
}
useEffect(() => {
const timer = setInterval(async() => {
console.log("Timer has started")
let prevRole = role;
let prevRoleIndex = roles.findIndex((ele)=>ele===prevRole)
console.log("Previous Role State: "+ prevRole)
for(let i=0; i<10; i++){
setRole(getRandomString())
await sleep(50)
}
prevRoleIndex = prevRoleIndex+1 >= roles.length? -1: prevRoleIndex
let newRole = roles[prevRoleIndex+1]
console.log("New Role State: "+ newRole)
setRole(newRole)
}, 3000);
return () => clearInterval(timer);
}, []);
return(
<div>
<h1>{role}</h1>
</div>
)
}
The code works fine during first timer iteration and after second iteration the state does not update.