Code files

Chapter05/communicating-with-websockets/websocket-client/index.js

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+'use strict'
+
+const WebSocket = require('ws')
+const readline = require('readline')
+const ws = new WebSocket(process.argv[2] || 'ws://localhost:8080')
+const rl = readline.createInterface({
+  input: process.stdin,
+  output: process.stdout,
+  prompt: '-> '
+})
+const gray = '\u001b[90m'
+const red = '\u001b[31m'
+const reset = '\u001b[39m'
+ws.on('open', () => {
+  rl.output.write(`${gray}-- Connected --${reset}\n\n`)
+  rl.prompt()
+})
+rl.on('line', (msg) => {
+  ws.send(msg, () => {
+    rl.output.write(`${gray}<= ${msg}${reset}\n\n`)
+    rl.prompt()
+  })
+})
+ws.on('message', function (msg) {
+  readline.clearLine(rl.output)
+  readline.moveCursor(rl.output, -3 - rl.line.length, -1)
+  rl.output.write(`${gray}=> ${msg}${reset}\n\n`)
+  rl.prompt(true)
+})
+ws.on('close', () => {
+  readline.cursorTo(rl.output, 0)
+  rl.output.write(`${gray}-- Disconnected --${reset}\n\n`)
+  process.exit()
+})
+ws.on('error', (err) => {
+  readline.cursorTo(rl.output, 0)
+  rl.output.write(`${red}-- Error --${reset}\n`)
+  rl.output.write(`${red}${err.stack}${reset}\n`)
+})