pipeで繋いだStreamが例外を発行した場合の処理 ref: http://qiita.com/ishiduca/items/30ef3a4db72124ff9926

error.test.js

var test   = require('tape').test
var stream = require('stream')

function setup (src) {
    var queue = src.slice(0)
    var rs    = new stream.Readable({objectMode: true})
    rs._read  = function () {
        this.push(queue.shift() || null)
    }

    var ws = new stream.Writable({objectMode: true})
    ws.spy = []
    ws._write = function (chnk, enc, done) {
        this.spy.push(chnk)
        done()
    }

    var ts = new stream.Transform({objectMode: true})
    ts.spy = []
    ts._transform = function (chnk, enc, done) {
        if (chnk.sError)
            return done(chnk.sError)

        this.spy.push(chnk)
        this.push(chnk)
        done()
    }

    return {
        rs: rs
      , ws: ws
      , ts: ts
    }
}

test('transformStreamがエラーを発生させた場合 # リカバリーしない', function (t) {
    var error = new Error('foo is not bar')
    var src = [
        {sError: false, value: 'abc'}
      , {sError: error, value: 'def'}
      , {sError: false, value: 'ghi'}
    ]
    var ss = setup(src)
    var rs = ss.rs
    var ts = ss.ts
    var ws = ss.ws
    var spy = []

    Object.keys(ss).forEach(function (name) {
        ss[name].on('error', function (err) {
            spy.push(name + ' error ' + err.message)
        })
    })

    rs.on('end', function () { spy.push('rs end') })
    ts.on('finish', function () { spy.push('ts finish') })
    ts.on('end', function () { spy.push('ts end') })
    ws.on('finish', function () { spy.push('ws finish') })

    rs
      .pipe(ts)
      .pipe(ws)

    setTimeout(function () {
        t.deepEqual(rs._readableState.buffer, [{sError: false, value: 'ghi'}])
        t.deepEqual(spy, ['ts error foo is not bar'])
        t.deepEqual(ts.spy, [ {sError: false, value: 'abc'} ])
        t.deepEqual(ws.spy, [ {sError: false, value: 'abc'} ])
        t.end()
    }, 1000)
})

test('transformStreamがエラーを発生させた場合 # on("error")の中でpipeを繋ぎ直す', function (t) {
    var error = new Error('foo is not bar')
    var src = [
        {sError: false, value: 'abc'}
      , {sError: error, value: 'def'}
      , {sError: false, value: 'ghi'}
    ]
    var ss = setup(src)
    var rs = ss.rs
    var ts = ss.ts
    var ws = ss.ws
    var spy = []

    Object.keys(ss).forEach(function (name) {
        ss[name].on('error', function (err) {
            spy.push(name + ' error ' + err.message)
        })
    })

    ts.on('error', function () {
        rs.unpipe(ts)
        ts.unpipe(ws)
        rs.pipe(ts).pipe(ws)
    })

    rs.on('end', function () { spy.push('rs end') })
    ts.on('finish', function () { spy.push('ts finish') })
    ts.on('end', function () { spy.push('ts end') })
    ws.on('finish', function () { spy.push('ws finish') })

    rs
      .pipe(ts)
      .pipe(ws)

    setTimeout(function () {
        t.deepEqual(rs._readableState.buffer, [])
        t.deepEqual(spy, ['ts error foo is not bar', 'rs end', 'ts finish', 'ts end', 'ws finish'])
        t.deepEqual(ts.spy, [{sError: false, value: 'abc'}, {sError: false, value: 'ghi'}])
        t.deepEqual(ws.spy, [{sError: false, value: 'abc'}, {sError: false, value: 'ghi'}])
        t.end()
    }, 1000)
})

file1.js

ts.on('error', ...)

file2.js

ts.on('unpipe', functon (src) {
    src.pipe(this)
})