feat(types): Add DefaultEnv for zero runtime factory

[miyaji255]

Resolves #3793

This is BREAKING CHANGE.

I specified DefaultEnv for those that take Env as a type argument. By extending DefaultEnv with interface merging, you can change the default Env for various types.

This eliminates the need to use hono/factory in simple cases. However, if multiple Bindings are used, they must be explicitly specified.

interface DefaultEnv {}
interface DefaultBindings {}
interface DefaultVariables {}

export class Hono<E extends Env = DefaultEnv> {

Usage

By extending DefaultEnv, library users do not need to specify it explicitly.

// library
declare module "hono" {
  interface DefaultEnv {
    Bindings: DefaultBindings;
  }
  interface DefaultBindings {
    Foo: string;
  }
}

export function handle(app: Hono<any>): ...

You no longer need to explicitly specify Env.

import { Hono } from "hono";
import { handle } from "hono/aws-lambda/api-gateway";

const middleware: MiddlewareHandler = (c, next) => {
  c.env.event // APIGatewayProxyEvent
  c.env.lambdaContext // LambdaContext
  return next();
}

const app = new Hono()
  .get("/", c => {
    c.env.event // APIGatewayProxyEvent
    c.env.lambdaContext // LambdaContext
    return c.text(c.env.event.path);
  });
export default handle(app);

[yusukebe]

Hi @miyaji255

Thank you for the PR! I also think it would be good if we could set the env with declare module 'hono'. I'll start to consider this feature.

[miyaji255]

Thank you very much. I will also think about whether I can fix errors and design a better API.