how do i run an animation in a while loop?

so im trying to run an animation in a while loop but the animation just stops working and it doesnt work right

idk whats wrong but here is my code

local slash1 = Instance.new("Animation")
slash1.AnimationId = "http://www.roblox.com/Asset?ID=166956234"
local swordslash1 = game.Players.LocalPlayer.Character.Humanoid:LoadAnimation(slash1)

function swordslash()
    print'animating'
    animating = true
    swordslash1:Play()
    wait(3)
    animating = false
end

animating = false
function update() 
    if script.Parent.Equipped.Value == "IronSword" then

        sword.BrickColor = BrickColor.new("Dark stone grey")
        mesh.MeshId = "rbxasset://fonts/sword.mesh"
        mesh.TextureId = ""

        if script.Parent.Button1DownValue.Value == true then
            if animating == false then
                swordslash()
            end
        end
    end
end

while wait() do
    update()
end