JavaScript False Test

This test compares true/false in JavaScript with the C-sytle truthy/falsy behavoir. Additionally, isSet() function test is included to illustrate how to force expected OOP true/false behavoir. I also threw in an isEmpty() test, as an example of code using truthiness.

How to play: Click start test.

False and Falsy, WTF
Desc Code Test Result
false is false 
var o = false;
                    
(! o)? 'false': 'true';
true is true 
var o = true;
                    
(! o)? 'false': 'true';
null is falsy 
var o = null;
                    
(! o)? 'false': 'true';
undefined is falsy 
var o = undefined;
                    
(! o)? 'false': 'true';
0 is false 
var o = 0;
                    
(! o)? 'false': 'true';
1 is true 
var o = 1;
                    
(! o)? 'false': 'true';
'' is false 
var o = '';
                    
(! o)? 'false': 'true';
' ' is true 
var o = ' ';
                    
(! o)? 'false': 'true';
1-1 is false, numeric 0 
var o = 1-1;
                    
(! o)? 'false': 'true';
'1'-'1' is false, strings coerced to number and numeric 0 
var o = '1'-'1';
                    
(! o)? 'false': 'true';
'0'+'0' is true, strings concated 
var o = '0'+'0';
                    
(! o)? 'false': 'true';
0+'0' is true, strings concated 
var o = 0+'0';
                    
(! o)? 'false': 'true';
0+0 is false, numeric 0 
var o = 0+0;
                    
(! o)? 'false': 'true';
empty Object is true 
var o = {};
                    
(! o)? 'false': 'true';
empty Array is true 
var o = [];
                    
(! o)? 'false': 'true';
Force Expected False Behavoir with isSet()
Desc Code Test Result
false is set 
var o = false;
                    
isSet(o)? 'set': 'not set';
true is set 
var o = true;
                    
isSet(o)? 'set': 'not set';
null is not set 
var o = null;
                    
isSet(o)? 'set': 'not set';
undefined is not set 
var o = undefined;
                    
isSet(o)? 'set': 'not set';
0 is set 
var o = 0;
                    
isSet(o)? 'set': 'not set';
1 is set 
var o = 1;
                    
isSet(o)? 'set': 'not set';
Test if Objects & Arrays are Empty with isEmpty()
Desc Code Test Result
empty Object is true 
var o = {};
                    
isEmpty(o)? 'empty': 'not empty';
empty Array is true 
var o = [];
                    
isEmpty(o)? 'empty': 'not empty';
unempty Object is false 
var o = {test: 1};
                    
isEmpty(o)? 'empty': 'not empty';
unempty Array is false 
var o = ['test'];
                    
isEmpty(o)? 'empty': 'not empty';