file-type
Detect the file type of a file, stream, or data
cfb
Compound File Binary File Format extractor
officecrypto-tool
officeCrypto is a library for node.js that can be used to decrypt and encrypt excel files.
@sgtpooki/file-type
An *Ackchyually* browser compatible file-type hacky replacement of the `file-type` package. Forked from https://github.com/sindresorhus/file-type