TypeScript

TypeScript

TypeScript is a first-class language on Cloudflare Workers. Cloudflare publishes type definitions to GitHub and npm (npm install -D @cloudflare/workers-types). All APIs provided in Workers are fully typed, and type definitions are generated directly from workerd, the open-source Workers runtime.

Known issues

Transitive loading of @types/node overrides @cloudflare/workers-types

You project’s dependencies may load the @types/node package on their own. As of @types/node@20.8.4 that package now overrides Request, Response and fetch types (possibly others) specified by @cloudflare/workers-types causing type errors.

The way to get around this issue currently is to pin the version of @types/node to 20.8.3 in your package.json like this:

{
  "overrides": {
    "@types/node": "20.8.3"
  }
}

For more information, refer to this GitHub issue.

Resources

• TypeScript template
• @cloudflare/workers-types
• Runtime APIs
• TypeScript Examples