In exponent the base and its value can't be negative, then how modulus function is defined as $y=\sqrt{x^2}$ and $x$ can be any real number. [closed]

In exponent the base and its value can't be negative, then how modulus function is defined as $y=\sqrt{x^2}$ and $x$ can be any real number. As this modulus function is not obeying exponential definition.