potential reuse of mljs stuff

[kjappelbaum]

for small snippets such as https://github.com/YiuBen/jsDOE/blob/f819922e33b250152f3d8772bd0f34975ae98f95/src/utils.js#L1 might already be in mljs, e.g., https://github.com/mljs/spectra-processing/blob/20ab36d5ae888e93ff2321807ed34a1c1988b055/src/x/xMultiply.js#L8 and Luc likes reusing them.

another useful one might be some of the isArray checks

[YiuBen]

Thank you for the tips, I'll start using mljs when I can then