DNA strang.js

/*Deoxyribonucleic acid (DNA) is a chemical found in the nucleus of cells and carries the "instructions" for the development and functioning of living organisms.

If you want to know more: http://en.wikipedia.org/wiki/DNA

In DNA strings, symbols "A" and "T" are complements of each other, as "C" and "G". Your function receives one side of the DNA (string, except for Haskell); you need to return the other complementary side. DNA strand is never empty or there is no DNA at all (again, except for Haskell).

More similar exercise are found here: http://rosalind.info/problems/list-view/ (source) added to github

Example: (input --> output)

"ATTGC" --> "TAACG"
"GTAT" --> "CATA"*/

const DNAStrand = (dna) => {
    let sequence = {
      "A": "T",
      "T": "A",
      "G": "C",
      "C": "G"
    }
    return dna.replace(/A|T|G|C/g, x => {
      return sequence[x];
    });
  }