Exact Mass Database Manager (emdb)

emdb is a JavaScript/TypeScript library designed for managing and querying databases of molecular formulas, primarily focused on exact mass calculations in cheminformatics. It is part of the larger 'mass-tools' monorepo maintained by cheminfo. The library is currently stable at version 7.56.0 (as of April 2026), demonstrating a rapid release cadence with multiple updates often shipped monthly, indicating very active development. Key functionalities include loading various predefined chemical databases (e.g., test, KnapSack, commercial, contaminants), creating custom molecular formula databases from structured arrays or Google Sheets, and providing robust utility modules for generating molecular formulas from peptide or nucleotide sequences. It enhances cheminformatics applications by offering precise mass calculations and comprehensive molecular formula manipulation, including detailed information such as exact mass, molecular weight, charge, OCL (Open Chemistry Libre), and mass spectrometry filter data.