Node: Reading Every Line in a File

In Groovy this would be concise: new File(filename).eachLine { ... }. Here's what it looks like in Node using CoffeeScript:

fs = require('fs')
EM = require('events').EventEmitter
ev = new EM()
stream = fs.createReadStream(filename)
buffer = new Buffer(0)
stream.on 'data', (data) ->
    nextBuffer = new Buffer(buffer.length+data.length)
    buffer.copy(nextBuffer)
    data.copy(nextBuffer, buffer.length)
    start = 0
    offset = buffer.length
    buffer = nextBuffer

    for i in [1..data.length]
        if data[i] == 10
            end = i+offset+1
            line = buffer.slice start, end
            start = end
            ev.emit "line", line.toString()

    buffer = buffer.slice start
            
stream.on 'end', () ->
    ev.emit 'line', buffer.toString() unless buffer.length == 0
    
ev.on 'line', (line) ->
    ...

Do you have a smarter way of doing this?

Edit: I'm reading a very large file with this code. That's why this isn't synchronous.