Welcome to the Treehouse Community
Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.
Looking to learn something new?
Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.
Start your free trial
Dennis Brown
28,742 PointsWhy the long conditional?
I'm curious why you would want to look for "> 0", instead of just using the built-in value conditional from the value itself?
Example:
...
if(results.length) {
gifs = results.map(gif => {
...
I only ask this, because this is probably one of the most common conditional patterns I've seen used in React; not only for arrays, but also for boolean switches. It just looks and feels much cleaner, as well as much more dry. I'm sure it's mostly a styling choice, but I cannot think of a reason why it would be a logical choice since 0/undefined will always return false.
I guess I could say the same about the ternary parens in this case, but I know that is a styling choice.
Anyways, I thought I would at least bring it up.
2 Answers
Joe Beltramo
Courses Plus Student 22,191 PointsMost likely it is being specified for verbosity and learning. Shorthand the if clause to results.length is more 'advanced' to some. Should be safe to leave it as you have written it.
I would like to point out though that 0 (zero) and undefined will indeed be false, but in javascript -1 is not a falsy value. So be careful with that idea.
Craig Garner
25,732 PointsIf you don't have any images, that will be falsy.
Dennis Brown
28,742 PointsThat's the point. It's redundant. Instead you can use result.length as the conditional, as the return value of "0" will return false.
Jason Anello
Courses Plus Student 94,610 PointsJason Anello
Courses Plus Student 94,610 PointsHi Dennis,
Joe brings up an important point here for the general case.
In the general case, checking if a value is greater than 0 is not the same as checking if a value is truthy.
It's not a concern here because the length property can't be negative. But in general, it would be a concern.
Dennis Brown
28,742 PointsDennis Brown
28,742 PointsAh, great point!
Yes, for some reason I thought -1 was falsy, but ran another test to show it does return true. Of course I cannot think of a time an array would do this, and would need to use a method like indexOf for that to be an issue. The main concern though is the array, and testing for !0, and undefined if something was to happen with the state. It seems too redundant, and something I constantly see being used not only by myself. I understand making it explicit "just in case", but in a case like this there really isn't a reason to worry.
EDIT: Thanks for making me recheck that. I know there are a few conditionals that offer results not expected, and anything that watches for -1 (e.g. indexOf), I will use a conditional operator, otherwise I simply do not run across it. Still, it's great to remember, and I thank you for that.