In programming there is a lot of repetition. That’s the thing about computers, they can do stuff over and over again really efficiently. When you’re writing code for a program, there is a shortcut for doing things over and over again. It’s called a loop.
Let’s say you want a piece of code repeated a bunch of times, that’s what a loop can do for you.
We’ll start with the most basic loop, called the while loop. It’s like the if-statement where if something is true it will do something, except it will do that thing over and over again.
Start with while, then parentheses, inside the parentheses, we put our condition. Then, braces, this is where we put the statements or functions we want to execute.
Let’s set a variable counter equal to 0. Then in our while loop parentheses we’ll check if counter is less than or equal to 10. Then let’s add console log “I’ll be back” as the statement to run while the counter is less than or equal to 10. If we just ran it like this it would crash the browser since it would be an infinite loop. The counter value would never be greater than 10, so, the condition would never be false. Let’s log the counter variable, you’ll see it prints zero forever.
What we need to do is increment the counter. Remember the shortcut operator for this? It’s the plus plus operator. Let’s add that to the block.
Let’s add an alert that will run after the loop stops, we’ll do alert “hasta la vista baby” and concatenate the counter variable onto the end. Let’s run this shit!
And boom, hasta la vista baby, and the counter is equal to 11. During the last loop the counter value was 10, but got one more added on so the loop stopped and the alert was executed.