values, types, and operators

Question 1

Values of the number type are, unsurprisingly, _______ values.

Answer 1

numeric

Question 2

There are three special values in JavaScript that are considered numbers but don’t behave like normal numbers. They are _____, ______, and ______?

Answer 2

Infinity, -Infinity, NaN

Question 3

______s are used to represent text. They are written by enclosing their content in quotes.

Answer 3

string

Question 4

+, - , * , / , typeof are called _______

Answer 4

operators

Question 5

The minus sign - can be both a unary and binary operator. True/False

Answer 5

True

Question 6

Which operators are arithmetic ?

Answer 6

+, -, *, /, and %

Question 7

Which operators are or can be unary?

Answer 7

typeof and -

Question 8

The Boolean type has what to possible values?

Answer 8

True or False

Question 9

This one is called the conditional operator (or sometimes just the ______ operator since it is the only such operator in the language). true ? 1 : 2

Answer 9

Ternary

Question 10

____ and _____, that are used to denote the absence of a meaningful value. They are themselves values, but they carry no information.

Answer 10

null and undefined

Question 11

When something that doesn’t map to a number in an obvious way (such as “five” or undefined) is converted to a number, you get the value ______,

Answer 11

NaN

Question 12

When an operator is applied to the “wrong” type of value, JavaScript will quietly convert that value to the type it needs, using a set of rules that often aren’t what you want or expect. This is called __________.

Answer 12

type coercion

Question 13

console.log(8 * null)

Answer 13

0

Question 14

console.log(“5” - 1)

Answer 14

4

Question 15

console.log(“5” + 1)

Answer 15

51

Question 16

console.log(“five” * 2)

Answer 16

NaN

Question 17

console.log(false == 0)

Answer 17

true

Question 18

console.log(null == undefined);

Answer 18

true

Question 19

console.log(null == 0);

Answer 19

false

Question 20

When you want to test whether a value has a real value instead of _____ or _______, you can compare it to null with the == (or !=) operator.

Answer 20

null or undefined

Question 21

console.log(null || “user”)

Answer 21

user

Question 22

console.log(“Agnes” || “user”)

Answer 22

Agnes

Question 23

the second argument is executed or evaluated only if the first argument does not suffice to determine the value of the expression

Answer 23

short-circuit evaluation

Question 24

Which operator is used for string concatenation

Answer 24

+

Question 25

Which operators are used for comparison?

Answer 25

”==”, “!=”, “===”, “!==”, “”, “<=”, “>=”

Question 26

Which are the logic operators?

Answer 26

&&, ||

Question 27

is used to negate logically

Answer 27

!

Question 28

is used to negate a number

Answer 28

-