While loop

while loop ⇒ repeat some code While some condition is true

Normal code:

let username = "";
 
if(username === ""){
	console.log("you didn't enter your name");
}
else{
	console.log(`Hello ${username}`);
}

While code:

let username = "";
 
while(username === ""){
	console.log(`you didn't enter your name`);//this will repeat infinitely
}
 
console.log(`Hello ${username}`);

while will repeat the code infinitely while the condition is true

Final version:

let username = "";
 
while(username === "" || username === null){
	username = window.prompt(`Enter your name`)
}
 
console.log(`Hello ${username}`);}

Another example for login:

let loggedIn = false;
let username;
let password;
 
while(!loggedIn){
	username = window.window.prompt(`enter your username`);
	password = window.window.prompt(`enter your password`);
 
	if(username === "myusername" && password == "mypassword"){
		loggedIn = true;
		console.log("you are logged in!")
	}else{
		console.log("invalid credentials! Please try again")
	}
}