Truthy and Falsy Values
Name:
Date:
Class:
A
Quick Questions
Shade in the A or B circle for each question.
1. Is 0 a falsy value?
2. Is an empty string "" falsy?
3. Is the string "0" truthy?
4. Is an empty array [] falsy?
5. Is NaN a falsy value?
B
Match the Pairs
Draw a line connecting each item on the left to its match on the right.
| Left column | Right column | |
|---|---|---|
| 10 | AWrong - the string "0" is actually truthy | |
| 2"hello" | B"" | |
| 3The empty string, always falsy | CWrong - an empty array is actually truthy | |
| 4An empty array, actually truthy | DA falsy value - treated as false in a boolean context | |
| 5"0" is treated as falsy in an if statement | EA truthy value - treated as true in a boolean context | |
| 6[] is treated as falsy in an if statement | F[] |
C
Definitions
Falsy
D
Fill in the Blanks
Complete each line of code by filling in the missing parts.
1.
0 is a _____ value
2.
"" is a _____ value
3.
1 is a ______ value
4.
An empty string is a _____ value
5.
An array [] is a ______ value
E
Spot the Error
Shade in the letter of the line that contains an error.
Question 1
A
"" is truthy
B
0 is falsy
C
1 is truthy
Question 2
A
null is falsy
B
"0" is falsy
C
NaN is falsy
Question 3
A
false is falsy
B
undefined is falsy
C
[] is falsy
D
{} is truthy
Question 4
A
true is truthy
B
1 is truthy
C
-1 is truthy
D
0 is truthy
Question 5
A
false is falsy
B
0 is falsy
C
"" is falsy
D
null is falsy
E
1 is falsy
Answer Key
Truthy and Falsy Values
Section A: Quick Questions
Q1
A — Yes
Q2
B — Yes
Q3
A — Yes
Q4
A — No
Q5
B — Yes
Section B: Match the Pairs
Q1
0 → A falsy value - treated as false in a boolean context
Q2
"hello" → A truthy value - treated as true in a boolean context
Q3
The empty string, always falsy → ""
Q4
An empty array, actually truthy → []
Q5
"0" is treated as falsy in an if statement → Wrong - the string "0" is actually truthy
Q6
[] is treated as falsy in an if statement → Wrong - an empty array is actually truthy
Section C: Definitions
Q1
Falsy — A value that JavaScript treats as false in a boolean context, such as 0, "", null, undefined, or NaN.Section D: Fill in the Blanks
Q1
0 is a falsy valueQ2
"" is a falsy valueQ3
1 is a truthy valueQ4
An empty string is a falsy valueQ5
An array [] is a truthy valueSection E: Spot the Error
Q1
A — An empty string is falsy, not truthy.
Q2
B — The string "0" is actually truthy - it's not empty.
Q3
C — An empty array is truthy, not falsy.
Q4
D — 0 is falsy, not truthy.
Q5
E — 1 is truthy, not falsy.