feat: self-composing UseFN

packages/cloudwatch-metrics/index.d.ts

@@ -1,11 +1,19 @@
 import middy from '@middy/core'
+import { MetricsLogger } from 'aws-embedded-metrics'
+import type { Context as LambdaContext } from 'aws-lambda'
 export { MetricsLogger } from 'aws-embedded-metrics'
 
 interface Options {
   namespace?: string
   dimensions?: Array<Record<string, string>>
 }
 
-declare function cloudwatchMetrics (options?: Options): middy.MiddlewareObj
+export type Context = LambdaContext & {
+  metrics: MetricsLogger
+}
+
+declare function cloudwatchMetrics (
+  options?: Options
+): middy.MiddlewareObj<unknown, any, Error, Context>
 
 export default cloudwatchMetrics

packages/cloudwatch-metrics/index.test-d.ts

@@ -1,14 +1,14 @@
-import { expectType } from 'tsd'
 import middy from '@middy/core'
-import cloudwatchMetrics from '.'
+import { expectType } from 'tsd'
+import cloudwatchMetrics, { Context } from '.'
 
 // use with default options
 let middleware = cloudwatchMetrics()
-expectType<middy.MiddlewareObj>(middleware)
+expectType<middy.MiddlewareObj<unknown, any, Error, Context>>(middleware)
 
 // use with all options
 middleware = cloudwatchMetrics({
   namespace: 'myApp',
   dimensions: [{ Action: 'Buy' }]
 })
-expectType<middy.MiddlewareObj>(middleware)
+expectType<middy.MiddlewareObj<unknown, any, Error, Context>>(middleware)

packages/cloudwatch-metrics/package.json

@@ -68,7 +68,8 @@
     "aws-embedded-metrics": "3.0.0"
   },
   "devDependencies": {
-    "@middy/core": "3.1.1"
+    "@middy/core": "3.1.1",
+    "@types/aws-lambda": "^8.10.101"
   },
   "gitHead": "7a6c0fbb8ab71d6a2171e678697de9f237568431"
 }

packages/core/index.d.ts

@@ -1,7 +1,7 @@
 import {
+  Callback as LambdaCallback,
   Context as LambdaContext,
-  Handler as LambdaHandler,
-  Callback as LambdaCallback
+  Handler as LambdaHandler
 } from 'aws-lambda'
 
 declare type PluginHook = () => void
@@ -33,7 +33,7 @@ interface Request<TEvent = any, TResult = any, TErr = Error, TContext extends La
 
 declare type MiddlewareFn<TEvent = any, TResult = any, TErr = Error, TContext extends LambdaContext = LambdaContext> = (request: Request<TEvent, TResult, TErr, TContext>) => any
 
-export interface MiddlewareObj<TEvent = any, TResult = any, TErr = Error, TContext extends LambdaContext = LambdaContext> {
+export interface MiddlewareObj<TEvent = unknown, TResult = any, TErr = Error, TContext extends LambdaContext = LambdaContext> {
   before?: MiddlewareFn<TEvent, TResult, TErr, TContext>
   after?: MiddlewareFn<TEvent, TResult, TErr, TContext>
   onError?: MiddlewareFn<TEvent, TResult, TErr, TContext>
@@ -53,12 +53,16 @@ export interface MiddyfiedHandler<TEvent = any, TResult = any, TErr = Error, TCo
   handler: (handler: MiddlewareHandler<LambdaHandler<TEvent, TResult>, TContext>) => MiddyfiedHandler<TEvent, TResult, TErr, TContext>
 }
 
-declare type AttachMiddlewareFn<TEvent = any, TResult = any, TErr = Error, TContext extends LambdaContext = LambdaContext> = (middleware: MiddlewareFn) => MiddyfiedHandler<TEvent, TResult, TErr, TContext>
+declare type AttachMiddlewareFn<TEvent = any, TResult = any, TErr = Error, TContext extends LambdaContext = LambdaContext> =
+  (middleware: MiddlewareFn<TEvent, TResult, TErr, TContext>) => MiddyfiedHandler<TEvent, TResult, TErr, TContext>
 
-declare type AttachMiddlewareObj<TEvent = any, TResult = any, TErr = Error, TContext extends LambdaContext = LambdaContext> = (middleware: MiddlewareObj) => MiddyfiedHandler<TEvent, TResult, TErr, TContext>
+declare type AttachMiddlewareObj<TEvent = any, TResult = any, TErr = Error, TContext extends LambdaContext = LambdaContext> =
+  (middleware: MiddlewareObj<TEvent, TResult, TErr, TContext>) => MiddyfiedHandler<TEvent, TResult, TErr, TContext>
 
 declare type UseFn<TEvent = any, TResult = any, TErr = Error, TContext extends LambdaContext = LambdaContext> =
-  (middlewares: MiddlewareObj<TEvent, TResult, TErr, TContext> | Array<MiddlewareObj<TEvent, TResult, TErr, TContext>>) => MiddyfiedHandler<TEvent, TResult, TErr, TContext>
+  <TMiddleware extends MiddlewareObj<any, any, Error, any>>(middlewares: TMiddleware | TMiddleware[]) => TMiddleware extends MiddlewareObj<infer TMiddlewareEvent, any, Error, infer TMiddlewareContext>
+    ? MiddyfiedHandler<TMiddlewareEvent & TEvent, TResult, TErr, TMiddlewareContext & TContext> // always true
+    : never
 
 declare type MiddlewareHandler<THandler extends LambdaHandler<any, any>, TContext extends LambdaContext = LambdaContext> =
   THandler extends LambdaHandler<infer TEvent, infer TResult> // always true
@@ -70,7 +74,7 @@ declare type MiddlewareHandler<THandler extends LambdaHandler<any, any>, TContex
  * @param handler your original AWS Lambda function
  * @param plugin wraps around each middleware and handler to add custom lifecycle behaviours (e.g. to profile performance)
  */
-declare function middy<TEvent = any, TResult = any, TErr = Error, TContext extends LambdaContext = LambdaContext> (handler?: MiddlewareHandler<LambdaHandler<TEvent, TResult>, TContext>, plugin?: PluginObject): MiddyfiedHandler<TEvent, TResult, TErr, TContext>
+declare function middy<TEvent = unknown, TResult = any, TErr = Error, TContext extends LambdaContext = LambdaContext> (handler?: MiddlewareHandler<LambdaHandler<TEvent, TResult>, TContext>, plugin?: PluginObject): MiddyfiedHandler<TEvent, TResult, TErr, TContext>
 
 declare namespace middy {
   export {

packages/http-content-negotiation/index.d.ts

@@ -12,6 +12,19 @@ interface Options {
   failOnMismatch?: boolean
 }
 
-declare function httpContentNegotiation (options?: Options): middy.MiddlewareObj
+export interface Event {
+  preferredCharsets: string[]
+  preferredCharset: string
+  preferredEncodings: string[]
+  preferredEncoding: string
+  preferredLanguages: string[]
+  preferredLanguage: string
+  preferredMediaTypes: string[]
+  preferredMediaType: string
+}
+
+declare function httpContentNegotiation (
+  options?: Options
+): middy.MiddlewareObj<Event>
 
 export default httpContentNegotiation

packages/http-content-negotiation/index.test-d.ts

@@ -1,10 +1,10 @@
-import { expectType } from 'tsd'
 import middy from '@middy/core'
-import httpContentNegotiationMiddleware from '.'
+import { expectType } from 'tsd'
+import httpContentNegotiationMiddleware, { Event } from '.'
 
 // use with default options
 let middleware = httpContentNegotiationMiddleware()
-expectType<middy.MiddlewareObj>(middleware)
+expectType<middy.MiddlewareObj<Event>>(middleware)
 
 // use with all options
 middleware = httpContentNegotiationMiddleware({
@@ -18,4 +18,4 @@ middleware = httpContentNegotiationMiddleware({
   availableMediaTypes: ['application/xml', 'application/json'],
   failOnMismatch: true
 })
-expectType<middy.MiddlewareObj>(middleware)
+expectType<middy.MiddlewareObj<Event>>(middleware)

packages/http-event-normalizer/index.d.ts

@@ -1,5 +1,17 @@
 import middy from '@middy/core'
+import {
+  APIGatewayEvent,
+  APIGatewayProxyEventMultiValueQueryStringParameters,
+  APIGatewayProxyEventPathParameters,
+  APIGatewayProxyEventQueryStringParameters
+} from 'aws-lambda'
 
-declare function httpEventNormalizer (): middy.MiddlewareObj
+export type Event = APIGatewayEvent & {
+  multiValueQueryStringParameters: APIGatewayProxyEventMultiValueQueryStringParameters
+  pathParameters: APIGatewayProxyEventPathParameters
+  queryStringParameters: APIGatewayProxyEventQueryStringParameters
+}
+
+declare function httpEventNormalizer (): middy.MiddlewareObj<Event>
 
 export default httpEventNormalizer

packages/http-event-normalizer/index.test-d.ts

@@ -1,11 +1,11 @@
-import { expectType } from 'tsd'
 import middy from '@middy/core'
-import httpEventNormalizer from '.'
+import { expectType } from 'tsd'
+import httpEventNormalizer, { Event } from '.'
 
 // use with default options
 let middleware = httpEventNormalizer()
-expectType<middy.MiddlewareObj>(middleware)
+expectType<middy.MiddlewareObj<Event>>(middleware)
 
 // use with all options
 middleware = httpEventNormalizer()
-expectType<middy.MiddlewareObj>(middleware)
+expectType<middy.MiddlewareObj<Event>>(middleware)

packages/http-event-normalizer/package.json

@@ -63,6 +63,7 @@
   "homepage": "https://middy.js.org",
   "gitHead": "7a6c0fbb8ab71d6a2171e678697de9f237568431",
   "devDependencies": {
-    "@middy/core": "3.1.1"
+    "@middy/core": "3.1.1",
+    "@types/aws-lambda": "^8.10.101"
   }
 }

packages/http-header-normalizer/index.d.ts

@@ -5,6 +5,12 @@ interface Options {
   canonical?: boolean
 }
 
-declare function httpHeaderNormalizer (options?: Options): middy.MiddlewareObj
+export interface Event {
+  rawHeaders: Record<string, string>
+}
+
+declare function httpHeaderNormalizer (
+  options?: Options
+): middy.MiddlewareObj<Event>
 
 export default httpHeaderNormalizer

packages/http-header-normalizer/index.test-d.ts

@@ -1,14 +1,14 @@
-import { expectType } from 'tsd'
 import middy from '@middy/core'
-import httpHeaderNormalizer from '.'
+import { expectType } from 'tsd'
+import httpHeaderNormalizer, { Event } from '.'
 
 // use with default options
 let middleware = httpHeaderNormalizer()
-expectType<middy.MiddlewareObj>(middleware)
+expectType<middy.MiddlewareObj<Event>>(middleware)
 
 // use with all options
 middleware = httpHeaderNormalizer({
   normalizeHeaderKey: (key: string) => key.toLowerCase(),
   canonical: false
 })
-expectType<middy.MiddlewareObj>(middleware)
+expectType<middy.MiddlewareObj<Event>>(middleware)

packages/http-json-body-parser/index.d.ts

@@ -1,9 +1,19 @@
 import middy from '@middy/core'
+import { APIGatewayEvent } from 'aws-lambda'
+import { JsonValue } from 'type-fest'
 
 interface Options {
   reviver?: (key: string, value: any) => any
 }
 
-declare function jsonBodyParser (options?: Options): middy.MiddlewareObj
+export type Event = Omit<APIGatewayEvent, 'body'> & {
+  /**
+   * The body of the HTTP request.
+   */
+  body: JsonValue
+  rawBody: string
+}
+
+declare function jsonBodyParser (options?: Options): middy.MiddlewareObj<Event>
 
 export default jsonBodyParser

packages/http-json-body-parser/index.test-d.ts

@@ -1,13 +1,13 @@
-import { expectType } from 'tsd'
 import middy from '@middy/core'
-import jsonBodyParser from '.'
+import { expectType } from 'tsd'
+import jsonBodyParser, { Event } from '.'
 
 // use with default options
 let middleware = jsonBodyParser()
-expectType<middy.MiddlewareObj>(middleware)
+expectType<middy.MiddlewareObj<Event>>(middleware)
 
 // use with all options
 middleware = jsonBodyParser({
   reviver: (key: string, value: any) => Boolean(value)
 })
-expectType<middy.MiddlewareObj>(middleware)
+expectType<middy.MiddlewareObj<Event>>(middleware)

packages/http-json-body-parser/package.json

@@ -67,7 +67,9 @@
     "@middy/util": "3.1.1"
   },
   "devDependencies": {
-    "@middy/core": "3.1.1"
+    "@middy/core": "3.1.1",
+    "@types/aws-lambda": "^8.10.101",
+    "type-fest": "^2.18.0"
   },
   "gitHead": "7a6c0fbb8ab71d6a2171e678697de9f237568431"
 }