Javascript Logical Operator OR

Question

I would imagine this is a pretty standard Javascript logical operator example, but I found it funny that a typo made the answer correct. When bored = fasle (false spelt incorrectly), the code executed correctly. Why does "fasle" work? Any input is appreciated.

 var tired = false; var bored = true; var nap = function() { nap = tired || bored; bored = fasle; //tired = false; if ( nap = true) { console.log("they're both true!"); } else ( nap = false); { console.log("they're false!"); } };

Answer 1

fasle is evaluated as undefined , which then evaluates to false when converted to boolean.

But false === fasle evaluate to false, because they have different types.

This will give you an error in strict mode javascript, because undefined variables are not allowed in this case.

I guess your script can run "correctly" do have something to do with the browser you're using , which I denied at first. This will just cast an error, when tested on safari and chrome.

BTW, if ( nap = true) will always be true and if ( nap = false) will always be false. This is because = is assign operator while == is the equality comparison operator you want. Assign operator will always evaluate to the right operand.