GetInstanceAddedSignal

Function of:

Description:

GetInstanceAdded is given a tag (a string) and returns a signal which fires under two conditions:

The tag is assigned to an object within the DataModel (game) using CollectionService/AddTag
An object with the given tag is added as a descendant of the DataModel, e.g. by setting Instance/Parent or similar

Subsequent calls to this method with the same tag return the same signal object. Consider also calling CollectionService/GetTagged to get a list of objects that already have a tag (and thus won’t fire the event if they already are in the DataModel).

See also CollectionService/GetInstanceRemovedSignal, which returns an event that fires under similar conditions.

Parameters

Name	Type	Default	Description
Name tag	Type string	Default	Summary

Returns

Return Type	Summary
Return Type RBXScriptSignal	Summary

Code Samples

Deadly Bricks using CollectionService

This code sample causes any BasePart with the tag “Deadly” to kill any Humanoid that touches it. It does this using a common pattern with CollectionService: listen for all parts with the tag, and make a connection. When the tag is removed, disconnect. Instead of copying the same kill script into many bricks, use this pattern instead!

			
				CODE SAMPLE
			
				EXPECTED OUTPUT
			
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			local CollectionService = game:GetService("CollectionService")
local tag = "Deadly"

local function onDeadlyPartTouched(otherPart)
	if not otherPart.Parent then return end
	local human = otherPart.Parent:FindFirstChildOfClass("Humanoid")
	if human then
		human.Health = 0
	end
end

-- Save the connections so they can be disconnected when the tag is removed
-- This table maps BaseParts with the tag to their Touched connections
local connections = {}

local function onInstanceAdded(object)
	-- Remember that any tag can be applied to any object, so there's no
	-- guarantee that the object with this tag is a BasePart.
	if object:IsA("BasePart") then
		connections[object] = object.Touched:Connect(onDeadlyPartTouched)
	end
end

local function onInstanceRemoved(object)
	-- If we made a connection on this object, disconnect it (prevent memory leaks)
	if connections[object] then
		connections[object]:disconnect()
		connections[object] = nil
	end
end

-- Listen for this tag being applied to objects
CollectionService:GetInstanceAddedSignal(tag):Connect(onInstanceAdded)

-- Also detect any objects that already have the tag
for _, object in pairs(CollectionService:GetTagged(tag)) do
	onInstanceAdded(object)
end
		
			Try tagging a part using `CollectionService` by pasting this into the Command bar:
`game:GetService("CollectionService"):AddTag(workspace.Part, "Deadly")`
Then, when you press Play and touch the brick with your character they should die.
		
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GetInstanceAddedSignal

Parameters

tag

Returns

RBXScriptSignal

Code Samples

Deadly Bricks using CollectionService