When generating an OPF the following error occurs, however you can successfully build the .epub containing a valid OPF without issue
html2epub --basedir=alice --format=opf
/usr/local/lib/node_modules/html2epub/lib/index.js:377
var digits = files.length.toString().length;
^
TypeError: Cannot read property 'length' of undefined
at buildOPF_manifest (/usr/local/lib/node_modules/html2epub/lib/index.js:377:21)
at html2epub.showOPF (/usr/local/lib/node_modules/html2epub/lib/index.js:433:5)
at Object.<anonymous> (/usr/local/lib/node_modules/html2epub/index.js:47:20)
at Module._compile (module.js:460:26)
at Object.Module._extensions..js (module.js:478:10)
at Module.load (module.js:355:32)
at Function.Module._load (module.js:310:12)
at Function.Module.runMain (module.js:501:10)
at startup (node.js:129:16)
at node.js:814:3
When generating an OPF the following error occurs, however you can successfully build the .epub containing a valid OPF without issue