dna-sequence-tools

Tiny, dependency-free helpers for manipulating DNA and RNA strings.

Nothing here talks to a network or reads a file — it's just pure functions over A/C/G/T (and U for RNA). IUPAC ambiguity codes (N, R, Y, ...) are deliberately unsupported so the complement table stays unambiguous.

Install

npm install dna-sequence-tools

Usage

import {
  reverseComplement,
  gcContent,
  transcribe,
  translate,
} from 'dna-sequence-tools';

reverseComplement('ATGC');       // 'GCAT'
gcContent('ATATGC');             // 0.3333...
transcribe('ATGCTT');            // 'AUGCUU'
translate('ATGAAATAAGGG');       // 'MK'  (stops at TAA)
translate('ATGTAA', { keepStop: true }); // 'M*'

API

| Function | Description | | --- | --- | | complement(seq) | DNA complement, 5'→3' order preserved | | reverseComplement(seq) | Opposite strand read 5'→3' | | gcContent(seq) | Fraction of G+C bases, in [0, 1] | | transcribe(seq) | Coding DNA → mRNA (T→U) | | rnaComplement(seq) | RNA complement (A↔U, G↔C) | | translate(seq, opts) | DNA → protein using NCBI table 1 | | countBases(seq) | { A, C, G, T } tallies |

Input is case-insensitive; output is upper-case. Invalid bases throw.

The codon table is NCBI translation table 1 (the standard code). Alternate codes are out of scope for now.

License

MIT