This javascript console log is confusing me. How can x which has the value of -1 be evaluated to true in the if statement where it false the line before it? Thanks
x = -1
-1
x == true
false
if(x){console.log('yes')}
yes
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Negative numbers (except zero) aren't falsey values. – isherwood May 03 '16 at 21:32
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See: http://stackoverflow.com/a/3619813 `x == true; // false` - the boolean is cast to a number in this case and thus the comparison becomes `-1 == 1 // false` – timolawl May 03 '16 at 21:39
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**Comparing** a value to a Boolean is *very* different from **converting** a value to a Boolean. – Felix Kling May 03 '16 at 21:41
2 Answers
1
When you test x in your if statement, you're not checking if x is true, you're checking if x is truthey. The rules for truthiness in javascript are:
empty strings are falsey. all other strings are truthy.
0 and NaN are falsey. all other numbers are truthy.
all objects and arrays are truthy.
null and undefined are falsey.
Raphael Serota
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