求教，node local.js后，请求网址时报 Cannot read property 'update' of undefined

[weih]

具体的报错信息：

const result = this.cipher.update(buf);
                                 ^

TypeError: Cannot read property 'update' of undefined
    at Encryptor.encrypt (/home/better/software/shadowsocks-node/encrypt.js:165:34)
    at WebSocket.<anonymous> (/home/better/software/shadowsocks-node/local.js:200:37)
    at emitNone (events.js:106:13)
    at WebSocket.emit (events.js:208:7)
    at WebSocket.setSocket (/home/better/software/shadowsocks-node/node_modules/_ws@3.3.3@ws/lib/WebSocket.js:167:10)
    at ClientRequest._req.on (/home/better/software/shadowsocks-node/node_modules/_ws@3.3.3@ws/lib/WebSocket.js:715:10)
    at emitThree (events.js:136:13)
    at ClientRequest.emit (events.js:217:7)
    at TLSSocket.socketOnData (_http_client.js:475:11)
    at emitOne (events.js:116:13)

机子的node版本为v8.12.0,系统为Ubuntu 16.04.4 LTS