determines if you can backstab

can-backstab.lua

-- Compiled with roblox-ts v2.1.0
local NORMALIZER_VECTOR3 = Vector3.new(1, 0, 1)
local CanBackstab = function(attacker, victim)
	local attackerHead = attacker:FindFirstChild("Head")
	if attackerHead and attackerHead:IsA("BasePart") then
		local victimHead = victim:FindFirstChild("Head")
		if victimHead and victimHead:IsA("BasePart") then
			local _exp = victim:GetPivot().Position * NORMALIZER_VECTOR3
			local _arg0 = attacker:GetPivot().Position * NORMALIZER_VECTOR3
			local attackerToVictim = (_exp - _arg0).Unit
			local attackerEyeLevel = (attackerHead.Position * NORMALIZER_VECTOR3).Unit
			local victimEyeLevel = (victimHead.Position * NORMALIZER_VECTOR3).Unit
			return not (attackerToVictim:Dot(victimEyeLevel) <= 0 or (attackerToVictim:Dot(attackerEyeLevel) <= 0.5 or attackerEyeLevel:Dot(victimEyeLevel) <= -0.3))
		end
	end
	return false
end
local default = CanBackstab
return {
	CanBackstab = CanBackstab,
	default = default,
}

can-backstab.ts

const NORMALIZER_VECTOR3 = new Vector3(1, 0, 1);

export const CanBackstab = (attacker: Model, victim: Model) => {
	const attackerHead = attacker.FindFirstChild("Head");
	if (attackerHead && attackerHead.IsA("BasePart")) {
		const victimHead = victim.FindFirstChild("Head");
		if (victimHead && victimHead.IsA("BasePart")) {
			const attackerToVictim = victim
				.GetPivot()
				.Position.mul(NORMALIZER_VECTOR3)
				.sub(attacker.GetPivot().Position.mul(NORMALIZER_VECTOR3)).Unit;

			const attackerEyeLevel = attackerHead.Position.mul(NORMALIZER_VECTOR3).Unit;
			const victimEyeLevel = victimHead.Position.mul(NORMALIZER_VECTOR3).Unit;

			return !(
				attackerToVictim.Dot(victimEyeLevel) <= 0 ||
				attackerToVictim.Dot(attackerEyeLevel) <= 0.5 ||
				attackerEyeLevel.Dot(victimEyeLevel) <= -0.3
			);
		}
	}

	return false;
};

export default CanBackstab;