How toGenerate Cloudflare environment type with wrangler

If you're using wrangler to build app deployed to Cloudflare, there's a handy command this tool gives you that can generate a .d.ts file with all your .dev.vars and bindings configured in wrangler.toml.

wrangler types --env-interface RuntimeEnv ./types/cf.d.ts

The --env-interface RuntimeEnv option will set the name of the interface created and ./types/cf.d.ts is the file where it should be saved.

Let's say you have a .dev.vars like this:

.dev.vars
SESSION_SECRET="s3cr3t"

And a wrangler.toml like this:

name = "app-name"

[[d1_databases]]
binding = "DB"
database_name = "YOUR DATABASE NAME"
database_id = "YOUR DATABASE ID"

After running the command you will get this file:

types/cf.d.ts
// Generated by Wrangler on <DATE>
// by running `wrangler types --env-interface RuntimeEnv ./types/cf.d.ts`

interface RuntimeEnv {
	SESSION_SECRET: string;
	DB: D1Database;
}

This can then be used inside your app to type what your Cloudflare Pages and Workers receive from the context.