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JavaScript

Begana Choi
PLUS
Begana Choi
Courses Plus Student 13,126 Points
Posted by Begana Choi
Begana Choi
Courses Plus Student 13,126 Points

why 0(zero) is falsey?

I can't understand in this case, why zero is falsey.

function countToFive( start ){ start = start || 1; for ( var i = start; i <= 5; i += 1;){ console.log( i ); } }

countToFive(0)

because in my opinion, it is truthy when the start argument is given.

2 Answers

Ryan Groom
Ryan Groom
18,674 Points

Begana Choi I'm not really certain how 0's truth value relates to the function you pasted here, and I'm not certain this answers your question, but the explicit number 0 is ALWAYS falsey. If you do a "console.log(0 == false);" it will come out as a true statement because in programming the number 0 is representative of "false" and the number 1 is representative of "true". If this doesn't answer your question, I am going to need you to clarify a little more about the function you pasted and its context.

Begana Choi
Begana Choi
Courses Plus Student 13,126 Points
Begana Choi
Begana Choi
Courses Plus Student 13,126 Points

if I try it on console, 0 == false is true but 0 === false is false. I don't know how == works exactly yet, so I need to get an answer more precisely.. and the question is related with the video of short circuit evaluation!

Ryan Groom
Ryan Groom
18,674 Points

Begana Choi == is an operator that checks whether or not the value of two things are equal. === is an operator that checks that both the value AND the type of two things are equal. So in this instance 0 === false is false because 0 is a type "number" but the word false is a type "boolean". You can verify this in your console by using the typeof() function. You can do typeof(0) and typeof(false).