PhyloJS: Bridging phylogenetics and web development with a JavaScript utility library.

There is an increasing number of libraries devoted to parsing, manipulating and visualising phylogenetic trees in JavaScript. Many of these libraries bundle tree manipulation with visualisation, but have limited ability to manipulate trees and lack detailed documentation. As the number of web-based phylogenetic tools and the size of phylogenetics datasets increases, there is a need for a library that parses, writes and manipulates phylogenetic trees that is interoperable with other phylogenetic and data visualisation libraries. Here we introduce PhyloJS, a light zero-dependency TypeScript and JavaScript library for reading, writing and manipulating phylogenetic trees. PhyloJS allows for modification of and data-extraction from trees to integrate with other phylogenetics and data visualisation libraries. It can swiftly handle large trees, up to at least 10 6 tips in size, making it ideal for developing the next generation of more complex web-based phylogenetics applications handling ever larger datasets. The PhyloJS source code is available on GitHub (https://github.com/clockor2/phylojs) and can be installed via npm with the command npm install phylojs. Extensive documentation is available at https://clockor2.github.io/phylojs/.