jacobbednarz / workers-types

TypeScript type definitions for authoring Cloudflare Workers.

Cloudflare Workers Types

⚠️ If you're upgrading from version 2, make sure to remove webworker from the lib array in your tsconfig.json. These types are now included in @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": "ES2020",
    "module": "CommonJS",
    "lib": ["ES2020"],
    "types": ["@cloudflare/workers-types"]
  }
}

Using bindings

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

bindings.d.ts

export {};

declare global {
  const MY_ENV_VAR: string;
  const MY_SECRET: string;
  const myKVNamespace: KVNamespace;
}

Auto-Generation

Types are automatically generated from the Workers runtime's source code on every release. However, these generated types don't include any generics or overloads, so to improve ergonomics, some of them are overridden.

The overrides directory contains partial TypeScript declarations. If an override has a different type classification than its generated counterpart – for example, an interface is declared to override a generated class definition – then the override is used instead of the generated output. However, if they're the same type classification (e.g. both the override and the generated output are using class), then their member properties are merged:

• Members in the override but not in the generated type are included in the output
• If a member in the override has the same name as one in the generated type, the generated one is removed from the output, and the override is included instead
• If the member is declared type never in the override, it is removed from the output

If a named type override is declared as a type alias to never, that named type is removed from the output.

JSDoc comments from overrides will also be copied over to the output.

Comment overrides can also be written in Markdown. The docs directory contains these overrides. 2^nd level headings are the names of top level declarations (e.g. ## `KVNamespace`), 3^rd level headings are for member names (e.g. ### `KVNamespace#put`), and 4^th level headings correspond to JSDoc sections for members:

• #### Parameters: a list with parameters of the form - `param`: param description, these will be formatted as @param tags
• #### Returns: contents will be copied as-is to the @returns tag
• #### Examples: fenced code blocks with the language set to js, ts, javascript or typescript will be copied to @example tags