Like Array.prototype.reduce
but for streams. Given a sync reduce function and an initial value it
will return a through stream that emits a single data event with the
reduced value once the input stream ends.
var reduce = require("stream-reduce");
process.stdin.pipe(reduce(function(acc, data) {
return acc + data.length;
}, 0)).on("data", function(length) {
console.log("stdin size:", length);
});npm install stream-reduce