How do I create an unsigned integer array of size 128 bits in JavaScript?

I can use Uint8Array for 8 bits, Uint32Array for 32 bits, but I can't find an alternative which allows me to use 128 bits. Is there a computationally and memory efficient way to store such values?

At the moment I'm just approximating it by using an Array, but that appears to be ~5x slower than a Uint32Array.

via Popey Gilbert