See this and many other articles at lucaspaganini.com
Falsy
Falsy values are values that are considered false
when encountered in a boolean context. That means values that become false
if you try to convert them to a boolean
.
Boolean('');
//=> false
Boolean(0);
//=> false
Boolean(null);
//=> false
The list grows over time, but currently, those are the falsy values in JavaScript:
false
-
0
-0
0n
representations of zero 3. ```""
''` empty string
null
undefined
-
NaN
not a number -
document.all
possibly
NOTE:
document.all
can also be falsy in a very specific edge case.
markdown
**document.all**
Objects are falsy if and only if they have the [[IsHTMLDDA]] internal slot.
That slot only exists in 'document.all' and cannot be set using JavaScript.
Truthy
Truthy values are the opposite. They are values that are considered true
when encountered in a boolean context.
ts
Boolean('abc');
//=> true
Boolean(1);
//=> true
Boolean([]);
//=> true
All values that are not falsy, are truthy.
Conclusion
References are in the references.
We release web development tutorials every two weeks. Consider subscribing if you're interested in that.
Have a great day, and I'll see you soon!
Top comments (0)