diceware generates passphrases using the diceware method.
It's worth noting that it's not recommended to use a computer to generate a Diceware phrase. If you want to generate passphrases in node.js, check out https://github.com/shimaore/password instead.
npm install diceware
diceware = require('diceware');
console.log(diceware()); // by default generates a 5 word phrase
console.log(diceware(10)); // but number of words can optionally be specified