Converting Node.js (benchmarks game) programs to TypeScript

I've been trying to convert Node.js (benchmarks game) programs to TypeScript — using *trial and error* and *dumb luck*.

[That has worked](https://benchmarksgame-team.pages.debian.net/benchmarksgame/fastest/node-typescript.html) for:

* binary-trees * mandelbrot * n-body * pidigits * regex-redux

But the converted `fannkuch-redux` program was considerably slower, and I failed to convert these programs:

* spectral-norm * reverse-complement * k-nucleotide * fasta

Please help!

Please convert those 5 Node.js programs and [contribute working TypeScript equivalents to the benchmarks game](https://salsa.debian.org/benchmarksgame-team/benchmarksgame/blob/master/CONTRIBUTING.md#contribute-source-code-for-measurement).