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hono/deno_dist/compose.ts
Yusuke Wada 733f05c21c refactor(types): more robust and flexible (#806)
* chore: denoify

* v3.0.0-rc.5

* refactor(types): more robust and flexible

* fixed some
2023-01-19 22:45:25 +09:00

83 lines
2.3 KiB
TypeScript

import { Context } from './context.ts'
import type { Env, NotFoundHandler, ErrorHandler } from './types.ts'
interface ComposeContext {
finalized: boolean
res: unknown
}
// Based on the code in the MIT licensed `koa-compose` package.
export const compose = <C extends ComposeContext, E extends Env = Env>(
middleware: Function[],
onNotFound?: NotFoundHandler<E>,
onError?: ErrorHandler<E>
) => {
const middlewareLength = middleware.length
return (context: C, next?: Function) => {
let index = -1
return dispatch(0)
function dispatch(i: number): C | Promise<C> {
if (i <= index) {
throw new Error('next() called multiple times')
}
let handler = middleware[i]
index = i
if (i === middlewareLength && next) handler = next
let res
let isError = false
if (!handler) {
if (context instanceof Context && context.finalized === false && onNotFound) {
res = onNotFound(context)
}
} else {
try {
res = handler(context, () => {
const dispatchRes = dispatch(i + 1)
return dispatchRes instanceof Promise ? dispatchRes : Promise.resolve(dispatchRes)
})
} catch (err) {
if (err instanceof Error && context instanceof Context && onError) {
context.error = err
res = onError(err, context)
isError = true
} else {
throw err
}
}
}
if (!(res instanceof Promise)) {
if (res !== undefined && 'response' in res) {
res = res['response']
}
if (res && (context.finalized === false || isError)) {
context.res = res
}
return context
} else {
return res
.then((res) => {
if (res !== undefined && 'response' in res) {
res = res['response']
}
if (res && context.finalized === false) {
context.res = res
}
return context
})
.catch((err) => {
if (err instanceof Error && context instanceof Context && onError) {
context.error = err
context.res = onError(err, context)
return context
}
throw err
})
}
}
}
}