Comparing nil to number

Help and Feedback Scripting Support
#1

While working on my npc script, I came across a problem. So bascilly I want to make it so that the npc repeatedly find a target, so when player respawns the npc can still find their rootpart. But problem is after the player dies, the npc doesn’t work anymore. It just stops. The error is on line 20

Here is the script:

local pathfindingservice = game:GetService("PathfindingService")
local dummy = script.Parent
local dummyHumanoid = script.Parent:WaitForChild("Humanoid")
local dummyRootPart = script.Parent:WaitForChild("HumanoidRootPart")

target = nil

function findTarget()
	if dummyHumanoid.Health > 0 then
		for i,v in pairs(game.Workspace:GetDescendants()) do
			if v:IsA("Model") then
			if v.Name ~= dummy.Name and v:FindFirstChild("HumanoidRootPart") and v:FindFirstChild("Humanoid").Health > 0 then
				target = v.HumanoidRootPart
				vHumanoid = v.Humanoid
				local path = pathfindingservice:CreatePath()
					path:ComputeAsync(dummyRootPart.Position,target.Position)
					if path.Status == Enum.PathStatus.Success then
				local waypoints = path:GetWaypoints()
						for i,waypoint in pairs(waypoints) do
					if check() <= 100 and target ~= nil then
						dummyHumanoid:MoveTo(waypoint.Position)
								dummyHumanoid.MoveToFinished:Wait()
								if check() <= 2 then
									vHumanoid:TakeDamage(5)
									wait(1)
									print("Taking damage, npc close")
									if vHumanoid.Health == 0 then
										target = nil
										print("Target dead")
									end
								end
							end
						end
					end
				end
			end
		end
	end
end

function check()
	if vHumanoid.Health > 0 then
		if target then
		magnitude = (dummyRootPart.Position - target.Position).Magnitude 
		return magnitude
		end
	end
end

while wait() do
	findTarget()
end
#2

I found a solution. The problem was the check() function. So what I did is bascilly create a seperate function name CheckDistance. And I put part1 and part2 as parameters. So then when I were to check the distance again, I put npcrootpart, and player root part as the parameters.

script:

local pathfindingservice = game:GetService("PathfindingService")
local dummy = script.Parent
local dummyHumanoid = script.Parent:WaitForChild("Humanoid")
local dummyRootPart = script.Parent:WaitForChild("HumanoidRootPart")

local Punch1 = script.Parent:WaitForChild("Punch1")
local Punch2 = script.Parent:WaitForChild("Punch2")

function playAnimations()
	local punch1loaded = dummyHumanoid:LoadAnimation(Punch1)
	local punch2loaded = dummyHumanoid:LoadAnimation(Punch2)
	punch1loaded:Play()
	wait(0.5)
	punch2loaded:Play()
end

target = nil

local function checkDistance(part1,part2)
	return(part1.Position - part2.Position).Magnitude
end

function findTarget()
	local distance = 100
	local attackRange = 2
	if dummyHumanoid.Health > 0 then
		for i,v in pairs(game.Workspace:GetDescendants()) do
			if v:IsA("Model") then
			if v.Name ~= dummy.Name and v:FindFirstChild("HumanoidRootPart") and v:FindFirstChild("Humanoid").Health > 0 then
				target = v.HumanoidRootPart
					vHumanoid = v.Humanoid
				local path = pathfindingservice:CreatePath()
					path:ComputeAsync(dummyRootPart.Position,target.Position)
					if path.Status == Enum.PathStatus.Success then
				local waypoints = path:GetWaypoints()
						for i,waypoint in pairs(waypoints) do
					if checkDistance(dummyRootPart,target) < distance then
						dummyHumanoid:MoveTo(waypoint.Position)
								dummyHumanoid.MoveToFinished:Wait()
								if checkDistance(dummyRootPart,target) <= attackRange then
									playAnimations()
									vHumanoid:TakeDamage(2.5)
									wait(0.5)
									vHumanoid:TakeDamage(2.5)
									print("Taking damage, npc close")
									if vHumanoid.Health == 0 then
										target = nil
										print("Target dead")
									end
								end
							end
						end
					end
				end
			end
		end
	end
end


while wait() do
	findTarget()
end