hpdf.js is a scrip to create PDFs in your browser (it is a port of libharu). Existing projects with the same goal lack a lot of features (e.g. custom fonts). hpdf.js supports custom fonts (Type1 and TTF), PNG, JPEG, and RAW images, password protection, text and link annotations, outlines, drawing function (lines, cycles etc.), encoding support, and more.
Pillow scans directories searching for CommonJS packages (package.json files) and makes the packages usable in the browser (i.e. the found packages and modules can be accessed using the require() function). It supports multiple js files per package (and the dot notation in the require function). It also supports non js files (PNG, JPEG, GIF, JSON, CSS, HTML, and MD). Pillow can operate in command line mode (pillowscan mydirectory) or in server mode (pillowserve mydirectory), in which case packages are remade on the fly each time they are loaded through HTTP.