Cloudflare Workers Types

Install

npm install -D @cloudflare/workers-types
-- Or
yarn add -D @cloudflare/workers-types

Usage

The following is a minimal tsconfig.json for use alongside this package:

tsconfig.json

{
  "compilerOptions": {
    "target": "esnext",
    "module": "esnext",
    "lib": ["esnext"],
    "types": ["@cloudflare/workers-types"]
  }
}

Compatibility dates

The Cloudflare Workers runtime manages backwards compatibility through the use of Compatibility Dates. Using different compatibility dates affects the runtime types available to your Worker, and so it's important you specify the correct entrypoint to the workers-types package to match your compatibility date (which is usually set in your wrangler.toml configuration file). workers-types currently exposes the following entrypoints to choose from:

@cloudflare/workers-types

The default entrypoint exposes the runtime types for a compatibility date before 2021-11-03.
@cloudflare/workers-types/2021-11-03

This entrypoint exposes the runtime types for a compatibility date between 2021-11-03 and 2022-01-31.
@cloudflare/workers-types/2022-01-31

This entrypoint exposes the runtime types for a compatibility date between 2022-01-31 and 2022-03-21.
@cloudflare/workers-types/2022-03-21

This entrypoint exposes the runtime types for a compatibility date between 2022-03-21 and 2022-08-04.
@cloudflare/workers-types/2022-08-04

This entrypoint exposes the runtime types for a compatibility date between 2022-08-04 and 2022-10-31.
@cloudflare/workers-types/2022-10-31

This entrypoint exposes the runtime types for a compatibility date between 2022-10-31 and 2022-11-30.
@cloudflare/workers-types/2022-11-30

This entrypoint exposes the runtime types for a compatibility date between 2022-11-30 and 2023-03-01.
@cloudflare/workers-types/2023-03-01

This entrypoint exposes the runtime types for a compatibility date between 2023-03-01 and 2023-07-01.
@cloudflare/workers-types/2023-07-01

This entrypoint exposes the runtime types for a compatibility date after 2023-07-01.
@cloudflare/workers-types/experimental

This entrypoint exposes the runtime types for the latest compatibility date. The types exposed by this entrypoint will change over time to always reflect the latest version of the Workers runtime.

To use one of these entrypoints, you need to specify them in your tsconfig.json. For example, this is a sample tsconfig.json for using the 2022-08-04 entrypoint.

{
  "compilerOptions": {
    "target": "esnext",
    "module": "esnext",
    "lib": ["esnext"],
    "types": ["@cloudflare/workers-types/2022-08-04"]
  }
}

Importable Types

It's not always possible (or desirable) to modify the tsconfig.json settings for a project to include all the Cloudflare Workers types. For use cases like that, this package provides importable versions of its types, which are usable with no additional tsconfig.json setup. For example:

import type { Request as WorkerRequest, ExecutionContext } from "@cloudflare/workers-types/experimental"

export default {
  fetch(request: WorkerRequest, env: unknown, ctx: ExecutionContext) {
    return new Response("OK")
  }
}

Using bindings

It's recommended that you create a type file for any bindings your Worker uses. Create a file named worker-configuration.d.ts in your src directory.

If you're using Module Workers, it should look like this:

// worker-configuration.d.ts
interface Env {
  MY_ENV_VAR: string;
  MY_SECRET: string;
  myKVNamespace: KVNamespace;
}

For Service Workers, it should augment the global scope:

// worker-configuration.d.ts
declare global {
  const MY_ENV_VAR: string;
  const MY_SECRET: string;
  const myKVNamespace: KVNamespace;
}
export {}

Wrangler can also generate this for you automatically from your wrangler.toml configuration file, using the wrangler types command.