Js Loops Flashcards
What is a loop in JavaScript?
A loop is a control structure that allows you to repeat a block of code multiple times.
True or False: Loops can only iterate over arrays.
False
What are the three main types of loops in JavaScript?
for loop, while loop, and do…while loop.
Fill in the blank: The ______ loop executes a block of code as long as a specified condition is true.
while
Which loop is guaranteed to execute at least once?
do…while loop
What is the syntax for a basic for loop?
for (initialization; condition; increment) { // code to be executed }
What does the ‘break’ statement do in a loop?
It terminates the loop and transfers control to the statement following the loop.
What does the ‘continue’ statement do in a loop?
It skips the current iteration and continues with the next iteration of the loop.
True or False: A for loop can be used to iterate over an object.
True
What will the following code output? for (let i = 0; i < 3; i++) { console.log(i); }
0, 1, 2
Which loop would you use when the number of iterations is known?
for loop
What is the difference between ‘while’ and ‘do…while’ loops?
‘while’ checks the condition before executing the loop, while ‘do…while’ checks after executing the loop.
Fill in the blank: The ‘for…in’ loop is used to iterate over the ______ of an object.
properties
What is the output of the following code? let arr = [1, 2, 3]; arr.forEach(num => console.log(num));
1, 2, 3
True or False: You can nest loops inside one another.
True
What is the purpose of the ‘for…of’ loop?
To iterate over iterable objects like arrays, strings, or collections.
What will happen if the loop condition is always true?
It will create an infinite loop.
How can you exit from an infinite loop in JavaScript?
By using the ‘break’ statement or stopping the execution in the environment.
What keyword is used to declare a loop variable in a for loop?
let
Fill in the blank: The ‘forEach’ method is available on ______.
arrays
What will the following code print? for (let i = 0; i < 5; i++) { if (i === 3) break; console.log(i); }
0, 1, 2
What is a common mistake when using loops with asynchronous code?
Not accounting for the asynchronous behavior, which can lead to unexpected results.
True or False: The ‘for’ loop can be used to loop through a string.
True
What does the following code do? for (let i = 0; i < 5; i++) { if (i % 2 === 0) continue; console.log(i); }
It prints odd numbers: 1, 3.
What is the syntax for a ‘while’ loop?
while (condition) { // code to be executed }
Which loop would you use if you need to execute code at least once regardless of the condition?
do…while loop
