来源慕课网
var Readable = require('stream').Readable
var Writable = require('stream').Writable
var readStream = new Readable()
var writStream = new Writable()
readStream.push('I')
readStream.push('Love')
readStream.push('Imooc\n')
readStream.push(null)
writStream._write = function (chunk,encode,cb) {
console.log(chunk.toString())
cb()
}
readStream.pipe(writStream)