``` Readable : 可读流 Writable : 可写流 Duplex: 既可读又可写 Transform : 操作写入的数据，然后读取结果，通常用于输入数据和输出数据不要求匹配的场景 ``` ### Readable ~~~ var fs = require('fs') var readStream = fs.createReadStream('test.txt', 'utf-8') readStream.on('data', function (data) { console.log(data) }) readStream.on('close', function () { console.log('close') }) readStream.on('error', function (err) { console.log(err) }) ~~~