Tutorial - Check if an object has property

[Xsticcy]

Hello developers!
Sometimes we need to know if an object has a specific property, I discovered a way to do this and decided to share it with you!
(I know others discovered this trick way before me!)

I can’t really explain the code, but here is it:

function hasProperty(object, propertyName)
    local success, _ = pcall(function() 
        object[propertyName] = object[propertyName]
    end)
    return success
end

--<< Example: >>--

print(hasProperty(workspace.Part, "Text")) -- prints false
print(hasProperty(someThing.TextLabel, "Text")) -- prints true

Yep, that’s all.
I hope I showed something new, bye!

[ToldFable (Fable)]

A less hacky alternative to doing this would be to use Anaminus’ api. It’s what Quenty uses for his Class Converter plugin.

https://anaminus.github.io/rbx/json/api/latest.json

[JorusRetorak (PogoTheMonkey)]

I am kind of confused. How is this a tutorial if you don’t explain it at all? Kind of seems more like a community resource.

[Xsticcy]

This code is so short I can’t explain anything about it.
I don’t feel like this is a community resource, this is like a little “code trick”.

[JorusRetorak (PogoTheMonkey)]

A tutorial is explain it though, this is giving the code out for people who need it, it would be a community resource.

[octav20071 (OctaViano)]

I have a question, would the following would be affected or not?
Let’s say I use this function in a for loop, and check with Decals and BaseParts. They both have Transparency, but it’s not the same when you select both part and decal in properties tab. What would happen?

[Xsticcy]

I think it would still work.
It’ll return true for both, because they have a property named “Transparency”.

[RecanValor (recanman)]

Ah yes, totally your code:

How to check if an Instance has Certain Properties?

Perhaps a way to do this is, using pcall. You can do some hacky trickery, by calling a function that’s supposed to just do object.Transparency, if Transparency didn’t exist, pcall will return false (because the function errored), if it existed it returns true (because it functioned correctly). local function hasProperty(object, prop) local t = object[prop] --this is just done to check if the property existed, if it did nothing would happen, if it didn't an error will pop, the object[prop] i…

[Xsticcy]

Now, I don’t knwo what are you talking about.
This code is NOT the same as mine. Even the variable names are different.
And I mentioned:

@Xsticcy

(I know others discovered this trick way before me!)

I won’t post a copy-paste version of somebody else.

[jers_e]

Bro that’s a huge waste of the pcall function…

[Xsticcy]

Now, I know I could do it with :FindFirstChild() too. But I figured out this first and it gets the job done.

[debugger57]

There is a reason why :FindFirstChild() has word “child” in its name - :FindFirstChild() is for getting object’s children, it doesn’t work with properties.

Thanks for tutorial. It helped me a lot.

[debugger57]

If you are talking about :FindFirstChild() , then no, it doesnt work with properties.

[Gojinhan (HashCollision)]

Also i’d like to make a comment on this resource in general, you don’t really need this very much, an easier way would be to not loop through a varying table, identify members through a more conventional way, etc. Generally relying on pcalls for anything like this is pretty redundant.