Dot product?

[Rudxain]

I don't see any reason to add this because:

• Math methods don't expect arrays, the only thing similar to that is making use of rest params or the local arguments object.
• It's not a commonly used operation, although more frequently used than matrix multiplication.
• It's easy to implement in userland (see polyfill at the footer).

However some reasons to add it may be:

• Users/devs don't need to think about how to handle arrays with different lengths, because it would be standardized.
• Less rounding errors, because implementations could use Kahan Summation or Pairwise Sum internally (related: Issue Math.sum? #4 ).

I think this shouldn't be added because, as said before, it would break the consistency of Math.*. This is better suited for the Array namespace or a new namespace, which are both out of scope of this proposal. I opened this Issue just in case someone has valid (and solid) arguments for adding it.

Polyfill:

Math.dotProd = function(arr0, arr1) {
  return arr0.map((_, i) => arr0[i] * arr1[i]).reduce((x, y) => x + y);
}

Wikipedia article