官方介绍称，Node.js 21 最大的亮点之一包含内置 WebSocket 客户端，可直接通过带有 Node.js 的程序连接至 WebSocket 服务器，而无需再依赖第三方套件库。

Node.js is single-threaded, and because there is very little resource overhead to responding to a WebSocket event, the server generally handles the flood of events without issue.

Node.js 21, the latest release of the open source cross-platform JavaScript runtime, has arrived, featuring a built-in WebSocket client and support for globs in the platform’s test runner.