node-bufferize
Example
var bufferize = require("bufferize");
var es = require("event-stream");
var fs = require("fs");
fs.createReadStream("dictionary.txt", { encoding: 'utf8' })
.pipe(es.split())
// A stream event per word in the dictionary
.pipe(bufferize(512))
// A stream event per 512 word in the dictionary (array of words)
.pipe(...)
...