Hello! So, I’ve recently found many people having troubles related to duplicated code, and scripting lots of parts in their games and I thought that this simple tutorial could help those developers.
But first things first, what’s CollectionService? Well, CollectionService is a Service that can be used to manage groups of instances using tags, a set of strings that aren’t visible without using a plugin, we’ll get on that later.
CollectionService is very useful, since it allows us to run scripts or change properties of large group of parts without having to do boring and long loops. Learning how to use this Service will save us tons of lanes of code.
Let’s start by learning some basic functions about CollectionService, let’s create our first tag and let’s tag our first part.
But before starting with the functions, let’s set up our variables
local CollectionService = game:GetService("CollectionService") --The main service
local Part = Instance.new("Part", workspace) --The part that we will tag
:AddTag(instance, string)
CollectionService:AddTag(Part, "testTag")
Our first function is :AddTag() and It will basically tag an instance with the given tag, or, if the tag does not exist, :AddTag() will create a new tag, and then will tag the given instance.
But we can’t know if the part is actually tagged, because the tag is invisible, so let’s see the next function
:GetTags(instance)
CollectionService:AddTag(Part, "testTag")
print(CollectionService:GetTags(Part)) --> {"testTag"}
:GetTags() will return a table with all the tags of a part, so now, if you print the output of this function, It should print something like this:
:GetTagged(string)
CollectionService:AddTag(Part, "testTag")
print(CollectionService:GetTagged("testTag"))
:GetTagged() is very similar to :GetTags(), but instead of returning the tags of an instance, it will return all the instances with a tag.
If we try to tag more parts, we will see that the table gets bigger
:RemoveTag(instance, string)
CollectionService:AddTag(Part, "testTag")
print(CollectionService:GetTags(Part))
CollectionService:RemoveTag(Part, "testTag")
print(CollectionService:GetTags(Part))
:RemoveTag(), removes a desired tag from an instance. And that’s all, as you can see in this example, if we print the tags of Part before removing them, we will get the table with testTag.
But if we print the tags of Part after removing them, we will get an empty table
:HasTag(instance, string)
--// The rest of the code was cut just to save space
CollectionService:AddTag(Part, "testTag")
if CollectionService:HasTag(Part, "testTag") then
print("Success")
else
print("Not success")
end
This is getting spicy, :HasTag() is a very useful function of CollectionService, and it basically checks if an instance, has got a specified tag, if that instance has got the specified tag, :HasTag() will return true. In this case we’re checking if the Part has got "testTag" and if it is true, we will print “Success”.
:GetInstanceAddedSignal() & :GetInstanceRemovedSignal()
--// The rest of the code was cut just to save space
CollectionService:GetInstanceAddedSignal("testTag"):Connect(function(Object)
print(Object.Name.." was tagged with testTag")
end)
CollectionService:GetInstanceRemovedSignal("testTag"):Connect(function(Object)
print(Object.Name.." got removed from testTag")
end)
CollectionService:AddTag(Part, "testTag") --// This will make the script print "Part was tagged with testTag"
CollectionService:RemoveTag(Part, "testTag") --// This will make the script print "Part got removed from testTag"
These 2 functions will fire the callback function when an instance is added/removed from a specified tag. The connected function will return the Instance that has been tagged/untagged as the first argument.
Now that we know all the functions, let’s see what we can do with this.
As said before, with CollectionService we can run codes or change properties of big groups of parts, how? Let’s take a look on how to do it.
So, Imagine that you have 3 parts and you want them to kill the player if it touches them, what would you do?
No! Never do that again, that’s time consuming and can even lead to problems.
Okay that’s better. In this situation, there are only 3 parts, so It would be very easy to get the 3 parts and connect them to a function, but imagine that instead of 3 parts, you have 500, uh, It wouldn’t be that easy to connect the 500 parts one by one. In this case, we can use CollectionService, which is way better than connecting each part one by one.
local CollectionService = game:GetService("CollectionService")
--// First, we will loop trough all the parts with the "killers" tag using a for loop.
for _, part in pairs(CollectionService:GetTagged("killers")) do
--[[
Now that we've got our killer parts, we're gonna bind them to a function,
so when they get touched, they will fire that function.
--]]
part.Touched:Connect(function(hit)
--// Classic killing brick script, nothing very interesting
if (hit.Parent:FindFirstChild("Humanoid")) then
local humanoid = hit.Parent.Humanoid
humanoid.Health = humanoid.Health - humanoid.MaxHealth
end
end)
end
And now we have our 3 functional killer parts, and everything in less than 25 lines of code and just using one script. The best thing of all is that we can easily change the script whenever we want and our parts will still work. Just imagine if you had to manage 300 killing bricks without CollectionService.
Well, maybe you’re thinking about using for loops to iterate through all the parts and connect them to a function, actually, that is what we did in the code above us, but there’s one little difference between using for loops and using CollectionService. If you wanted to use for loops to do this, you would have to give the parts a Key name or insert some sort of value into them so the script could know they are the correct parts, by using CollectionService, you can avoid those steps.
If you’re going to use CollectionService for your game, I really, really (just do it) recommend you installing Tag Editor Plugin, you can find a detailed explanation about it in the next paragraph.
Tag Editor Plugin
As I said before, @Sweetheartichoke’s plugin, Tag Editor Plugin, is basically a plugin that makes It easier & faster to manipulate tags on Roblox Studio.
If you want detailed information about the Plugin and you want to get it, check the original post linked above, but here I’m gonna show you the basics and how to use this plugin to make your life much more easier when using tags.
Let’s imagine I want to create a new tag for the killing parts, instead of creating a whole script using :AddTag() & looping through a folder or group of parts, I will open Tag Editor and I will type the name of my new tag
Press enter and… there it goes, your new tag without having to script nothing
Now that we have our tag, we just have to select the parts and apply that tag to the parts.
If you want to know if you really tagged your parts, you can check it out activating World View. (also from the Tag Editor Plugin).
And now you will be able to see an outline, or a box at all the parts tagged with the tag that you selected.
And now that you have your tags created, you can freely use them in your scripts, amazing!
Well, that’s all about CollectionService, hope It was useful. If you want to know more about the Tag Editor Plugin just go and check the official post and get it!
