Cram-JS

Cram-JS is a JavaScript library that addresses the complexities of handling the CRAM format, a compressed file format specifically optimized for storing DNA sequence data. The CRAM format is highly efficient, particularly for short-read sequencing data, as it aligns reads to a reference genome and utilizes a variety of encoding techniques, such as Huffman, subexponential, Elias gamma, rANS, and gzip codes, to significantly reduce storage costs associated with DNA sequencing data.

Before Cram-JS, no JavaScript implementation was available for the CRAM format, which limited the accessibility and manipulation of CRAM files within web-based genomic tools and applications. Cram-JS fills this gap by providing a robust and efficient library that natively reads and decompresses CRAM files on the fly. This capability is crucial for web-based genome browsers and bioinformatics tools, enabling them to handle CRAM files directly without needing server-side processing or conversion to other formats.

The library has been successfully integrated into popular genome browsers such as JBrowse and IGV-JS, demonstrating its utility and performance. Moreover, Cram-JS's design and implementation are based on the ES-6 standard, making it compatible with modern web development practices and easily integrated into web browser environments and Node.js applications.