Function (where I registered the function)

-- services
local replicatedStorage = game:GetService('ReplicatedStorage')

-- objects
local doorModules = replicatedStorage:WaitForChild('DoorModules')

-- variables
local functions = {}

function functions.GetClosestTrigger(player, door)
    local closest = {}
    local triggerModel = door:FindFirstChild('Trigger') or door:FindFirstChild('Triggers') or nil

    if triggerModel then
        for _, trigger in next, triggerModel:GetChildren() do
            if trigger:IsA('Model') then
                local mag = (trigger.PrimaryPart.Position - player.Character.HumanoidRootPart.Position).magnitude
                table.insert(closest, {
                    distance = player:DistanceFromCharacter(mag),
                    trigger = trigger
                })
            end
        end

        table.sort(closest, function(a, b)
            return (a.distance < b.distance)
        end)
    end

    return closest[1] or {}
end

function functions.GetClosestDoor(player, list)
    local closest = {}

    list = (type(list) == 'table') and list or list:GetChildren()
    for _, door in next, list do
        if door:IsA('Model') or door:IsA('UnionOperation') then
            local trigger = functions.GetClosestTrigger(player, door).trigger or door.PrimaryPart
            print(trigger)
            print(trigger.PrimaryPart)
            local mag = (trigger.PrimaryPart.Position - player.Character.HumanoidRootPart.Position).magnitude
            table.insert(closest, {
                door = door,
                trigger = trigger,
                distance = player:DistanceFromCharacter(mag),
            })
        end
    end

    table.sort(closest, function(a, b)
        return (a.distance < b.distance)
    end)
print(closest)
    return closest[1]
end

return functions