Loops

(for, while)

A loop repeats code multiple times without rewriting it.

for Loop (counted repetition)

for (let i = 1; i <= 5; i++) { console.log(“Jumping Jack #” + i); }

Explanation:

• let i = 1 starts the counter at 1
• i <= 5 keeps looping while i is 5 or less
• i++ adds 1 each time
• Code inside runs once per number

while Loop (repeat while condition is true)

let cookies = 3;

while (cookies > 0) { console.log(“Nom! Cookie eaten!”); cookies–; }

Explanation:

• Start with cookies = 3
• Keep looping while cookies > 0
• cookies– subtracts 1 each time
• Eventually cookies hits 0, and the loop stops

Mini-Quiz

1. Which loop is best when you know exactly how many times to repeat?
2. What does cookies– do?