#要約
　WebSocket通信のクライアント/サーバの環境を構築する。お仕事でWebSocket通信のツール、環境が必要となった際にまとめたものです。

wsのインストール

~/develop/wscatTest $ yarn init
yarn init v1.22.5
question name (wscatTest): 
question version (1.0.0): 
question description: 
question entry point (index.js): 
question repository url: 
question author: 
question license (MIT): 
question private: 
success Saved package.json
✨  Done in 2.88s.
~/develop/wscatTest $ yarn add ws
yarn add v1.22.5
info No lockfile found.
[1/4] 🔍  Resolving packages...
[2/4] 🚚  Fetching packages...
[3/4] 🔗  Linking dependencies...
[4/4] 🔨  Building fresh packages...

success Saved lockfile.
success Saved 1 new dependency.
info Direct dependencies
└─ ws@8.3.0
info All dependencies
└─ ws@8.3.0
✨  Done in 1.40s.
~/develop/wscatTest $

サーバ環境構築

~/develop/wscatTest $ npx wscat -l 3000
Listening on port 3000 (press CTRL+C to quit)

クライアント接続

~/develop/wscatTest $ npx wscat -c ws://localhost:3000
Connected (press CTRL+C to quit)

あとは文字を打てば動画の通りに動きます。