Imaginary unit before imaginary part of complex number using siunitx

Question

When using the siunitx package, how can I change the complex number format from 1+2j (or i) to 1+j2? The documentation calls this an "invalid arrangement", but it seems to be common in electrical engineering.

\documentclass{article}
\usepackage{siunitx}
\sisetup{output-complex-root=\ensuremath{j}}
\begin{document}
Default output: \num{1+j2}

Desired output: \(1+\mathrm{j}2\)
\end{document}

Answer 1

 \sisetup{output-complex-root=\ensuremath{j},
          complex-root-position=before-number}