How would you make a bullet go to the direction of the mouse?

local plr = game.Players.LocalPlayer
local mouse = plr:GetMouse()

local function computeDirection(vec)
    local lenSquared = vec.magnitude * vec.magnitude
    local invSqrt = 1 / math.sqrt(lenSquared)
    return Vector3.new(vec.x * invSqrt, vec.y * invSqrt, vec.z * invSqrt).unit
end

mouse.Button1Down:connect(function()
    if not plr.Character then return end
    local dir = computeDirection(mouse.Hit.p - plr.Character.Torso.Position)
    --'dir' is your direction.  Continue from here.
end)