Fetch Arguments

The fetch handler on Cloudflare Workers receives 3 arguments:

• [arg0] of type Request.
• [arg1] of type Env.
• [arg2] of type ExecutionContext.

These arguments are exposed on all Workery handler functions.

Argument Unpacking

Handler functions can unpack the previously mentioned arguments with the following keys:

• req of type Request.
• env of type Env.
• ctx of type ExecutionContext.

For example:

app.get("/", {
    parameters: {},
    handle: ({ req, env, ctx }) => {
        // ...
        return { message: "Hello World" }
    },
})

Env Type Inference

By default, env is typed as unknown. It's the developer's job to ensure that App instances knows the correct type for env. As shown in the previous examples in this documentation, App receives one generic type E, which represents your env type. Therefore, your app instantiation should look like this:

const app = new App<Env>({})

Worker Configuration

Ensure that your worker-configuration.d.ts has up to date Env types.

Dependency Env

When defining Dependencys, the recommended approach for typing env is a bit different, as this class holds additional generic types other than E, and TypeScript has yet to support partial type inference, providing the type for env can be troublesome.

A workaround and more comfortable way of providing the type for env is by passing it on the init parameter of:

const app = new App<Env>({})

const requireAuth = new Dependency({
    of: app,
    parameters: {
        authorization: Header(z.string()),
    },
    handle: async ({ env, authorization }) => {
        //...
    },
})

The dependency will inherit the env type in of and use it.

If for any reason you do not want to pass the App instance, you can use the helper class Of to achieve the same results:

import { Of } from "workery"

const requireAuth = new Dependency({
    of: new Of<Env>(),
    parameters: {
        authorization: Header(z.string()),
    },
    handle: async ({ env, authorization }) => {
        //...
    },
})