Loops (JavaScript)
Loops
> Tutorial
We are now going to look at another type of structure that is just as fundamental as conditions: loops!
A loop allows instructions to be repeated several times. There are several types, bounded and unbounded, that we will see in this part.
while loop
The unbounded while loop has a syntax similar to the if seen above. It allows an instruction block to be executed as long as a condition is met.
Here is an example:
This code will display in the logs when executed: > Counter is 1 Counter is 2 Counter is 3 Counter is 4 Counter is 5
do while loop
The unbounded do while loop is similar to the while loop, except that the condition occurs at the end, so the loop body is always executed at least once:
for loop
The for loop is a bounded loop that looks like a while loop but more condensed.
The for loop consists of three parts:
- Initialization: assigning a starting value to a
countervariable; - The condition: as long as it is valid, the loop continues to run;
- Incrementation: increase (or decrease) the value of your
countervariable.
Example of a for loop:
Attack multiple times in a row
Our leek has between 10 and 13 TP (thanks to Motivation) and the Pistol only costs 3 TP, so it can be used 4 times at most.
We use a for loop to execute the me.useWeapon() method 4 times in a row:
Here our variable i will have the values 0, 1, 2 and 3 so the loop will do 4 iterations.
❓ Quiz
What is a loop for?
Executing statements multiple times Condense your code Speed up part of your code Execute instructions in parallel
Which code(s) are correct?
let x = 0 while (x < 10) { x += 2 } let x = 0 for (let i = 0; i < 10) { x += 2 } let x = 0 while { x += 2 } do (x < 10) let x = 0 for (; x < 10;) { x += 2 }