Local development of remote/cloud functions has been various levels of painful ever since the computing trend started its rise, so it makes a lot of sense why Cloudflare would invest in easing that pain. Now they get to say developing with Cloudflare Workers is:

• 🎉 Fun: develop workers easily with detailed logging, file watching and pretty error pages supporting source maps.
• 🔋 Full-featured: supports most Workers features, including KV, Durable Objects, WebSockets, modules and more.
• ⚡ Fully-local: test and develop Workers without an internet connection. Reload code on change quickly.