API REFERENCE

Context

import { createContext } from '@rasenganjs/futon';
import type {
  Context,
  RuntimeContext,
  QueryParams,
  ServerInfo,
} from '@rasenganjs/futon';

See Context Object and Query Parameters for usage and examples.

createContext()

function createContext(
  request: Request,
  params?: Record<string, string>,
  runtime?: RuntimeContext
): Context;

Factory that builds a fresh Context for a single request. Called internally by Futon.fetch() — you won't normally call this yourself outside of tests. query and response are both created lazily on first access and cached thereafter.

Context

interface Context<
  Body = any,
  Params = Record<string, string>,
  Query = QueryParams,
> {
  request: Request;
  req: Request; // alias for `request`
  body: Body; // undefined until a body parser middleware sets it
  params: Params; // path params extracted by the Router
  query: Query & QueryParams; // lazily parsed, then cached
  runtime: RuntimeContext;
  response: ResponseBuilder; // lazily created, then cached
  res: ResponseBuilder; // alias for `response`
  state: Record<string, unknown>;
  set<T = unknown>(key: string, value: T): void;
  get<T = unknown>(key: string): T | undefined;
}
MemberDescription
request / reqThe incoming Web API Request.
bodyParsed request body. undefined until a body-parsing middleware (e.g. bodyParser()) runs.
paramsURL path parameters captured by the Router.
queryQuery parameters — both callable (ctx.query('page')) and indexable (ctx.query.page). See QueryParams.
runtimePlatform/environment info — see RuntimeContext.
response / resChainable ResponseBuilder for the fluent response API.
stateMutable bag for passing data between middleware and handlers (e.g. auth middleware sets state.user).
set(key, value)Store a value on state.
get(key)Read a value from state.

RuntimeContext

interface RuntimeContext {
  env?: Record<string, string>;
  server?: ServerInfo;
}

Carries platform-specific info so the same handler code runs unmodified on Node, Bun, Deno, and Cloudflare Workers. Accessible as ctx.runtime inside handlers/middleware.

ServerInfo

interface ServerInfo {
  preset: 'node' | 'bun' | 'express' | 'workerd' | 'wintercg' | 'unknown';
  mode: 'development' | 'production';
  port: number;
  host: string;
  rootDir: string;
}

Set by the runtime adapter before serving. Accessible via ctx.runtime.server inside the request lifecycle, or app.serverInfo outside of it (e.g. in onInit).

QueryParams

interface QueryParams {
  (key: string): string | undefined;
  [key: string]: string | undefined;
}

A callable-and-indexable object — ctx.query('page') and ctx.query.page both work. Parsed lazily from the URL on first access.

Router
Request