Double click instead of one click?

Have a bool which keeps track of if the player clicked previously in the past two seconds:

playerClicked = false

function clicked()
    -- if this is the first time the players clicked, start the countdown 
    if(not playerClicked)then 
        playerClicked = true --set the player clicked state to be true
        wait(2) -- give the player two seconds to click again
        -- if they don't click in the next two seconds, reset playerClicked to false
        playerClicked = false
    else -- the player clicked twice in the span of two seconds, do the following code you wanted them to do when they clicked twice
        local S = script.Parent.Parent.Parent.ScreenGui.Shop
            S:TweenPosition(UDim2.new(0.272, 0,0.279, 0))
            script.Parent.Parent.Parent.ScreenGui.Shop.Visible = true
    end
end
script.Parent.MouseButton1Click:Connect(clicked)