JS Jeopardy: Test Prep Edition

Variables & Data Types

100

What keyword should you use for a variable that will never be reassigned?

const

200

Give one valid JavaScript variable name that follows camel case rules.

myVariableName

300

What does the += operator do to a variable’s value?

Adds to its current value.

400

Which characters are allowed in JavaScript variable names (excluding the first character rule)?

Letters, numbers, _, and $

500

What happens if you try to use a variable that has been declared but not assigned a value?

It has the value undefined.

Strings

100

What property tells you the number of characters in a string?

.length

200

Which method checks if a string starts with certain text?

.startsWith()

300

What is the difference between .substring() and .slice()?

.slice() allows negative indexes; .substring() does not.

400

What will "Hello" + 5 return in JavaScript?

"Hello5" (string concatenation)

500

What method would you use to find the position of "cat" in "The cat sat"?

.indexOf("cat")

Functions

100

What keyword is used to define a function in JavaScript?

function

200

What are values placed inside a function’s parentheses when calling it called?

Arguments

300

What does the return keyword do in a function?

Sends a value back to where the function was called.

400

What is the difference between local and global variables?

Local variables exist only inside a function; global variables are accessible anywhere.

500

Write a function header for a function named add that takes two parameters, x and y.

function add(x, y) { }

Conditions

100

What keyword starts a conditional statement in JavaScript?

if

200

Which statement is best for checking one value against many fixed options?

switch statement

300

What does the ternary operator (? :) do?

Acts as a shorthand for if/else in assignments

400

What is the result of isNaN("Hello")?

true

500

Write a simple if statement that checks if score is greater than or equal to 90.

if (score >= 90) {

  // code

}

Operators

100

Which comparison operator checks both value and type?

===

200

What does true && false evaluate to?

false

300

Which logical operator returns true if at least one condition is true?

|| (OR)

400

What is the result of 5 != "5" in JavaScript?

false

500

What does the ! operator do to a Boolean value?

Reverses it (true becomes false, false becomes true).