for...of

JavaScript · Unit 3: Loops

for...of goes through a text letter by letter, with no counter and no condition.

On each round, the variable holds the next letter.

for (const letter of "sun") {
  console.log(letter);
}

Prints

s
u
n

The rest of the explanation is in the lesson, which is part of the full plan.

Exercises in this lesson

You do them in the app, which checks them on the spot and explains why.

1. Predict the output
What does this code print?
2. Predict the output
What does this code print?
3. Multiple choice
How many rounds does for (const c of "book") run?
4. Complete the code
Complete the loop header to print each letter of sun.
5. Predict the output
What does this code print?
6. Predict the output
What does this code print?
7. Find the bug
This program should build the text s-u-n-, with a dash after each letter. Which line has the error?
8. Put the lines in order
Put the lines in order to count how many a or e letters the word lemonade has.
9. Multiple choice
What does this code do?
10. Write the code
Write countA(text), which returns how many a letters the text has. For example, countA("banana") gives 3.

It opens in your browser. This lesson is part of the full plan; the first unit of each course is free.