Examples/framework koa (#393)

## Summary
<!-- Succinctly describe your change, providing context, what you've
changed, and why. -->

Add an `"inngest/koa"` serve handler.

## Checklist
<!-- Tick these items off as you progress. -->
<!-- If an item isn't applicable, ideally please strikeout the item by
wrapping it in "~~"" and suffix it with "N/A My reason for skipping
this." -->
<!-- e.g. "- [ ] ~~Added tests~~ N/A Only touches docs" -->

- [x] Added a [docs PR](https://github.com/inngest/website) that
references this PR
- [x] Added unit/integration tests
- [x] Added changesets if applicable

## Related

- Supersedes #252 
- Supersedes #262
- inngest/website#574

.changeset/itchy-tools-sin.md

@@ -0,0 +1,5 @@
+---
+"inngest": minor
+---
+
+Added a new `"inngest/koa"` serve handler. See the [Framework: Koa](https://www.inngest.com/docs/sdk/serve#framework-koa) docs and the [`framework-koa`](/examples/framework-koa) example to get started.

examples/.gitignore

@@ -1,3 +1,4 @@
 yarn.lock
 pnpm-lock.yaml
 package-lock.json
+bun.lockb

examples/framework-koa/.gitignore

@@ -0,0 +1,2 @@
+node_modules
+dist

examples/framework-koa/README.md

@@ -0,0 +1,31 @@
+# Inngest Koa Template
+
+This is a [Koa](https://koajs.com/) project . It is a reference on how to send and receive events with Inngest and Koa.
+
+## Getting Started
+
+## How to use
+
+Use [`create-next-app`](https://www.npmjs.com/package/create-next-app) with [npm](https://docs.npmjs.com/cli/init), [Yarn](https://yarnpkg.com/lang/en/docs/cli/create/), or [pnpm](https://pnpm.io) to bootstrap the example:
+
+```bash
+npx create-next-app --example https://github.com/inngest/inngest-js/tree/main/examples/framework-koa inngest-koa
+```
+
+```bash
+yarn create next-app --example https://github.com/inngest/inngest-js/tree/main/examples/framework-koa inngest-koa
+```
+
+```bash
+pnpm create next-app --example https://github.com/inngest/inngest-js/tree/main/examples/framework-koa inngest-koa
+```
+
+Open [http://localhost:3000](http://localhost:3000) with your browser to see the result.
+
+- [Inngest functions](https://www.inngest.com/docs/functions) are available at `src/inngest/`.
+- The [Inngest handler](https://www.inngest.com/docs/frameworks/nextjs) is available a `src/index.ts`.
+
+## Learn More
+
+- [Inngest Documentation](https://www.inngest.com/docs) - learn about the Inngest SDK, functions, and events
+- [Koa Documentation](https://koajs.com/) - learn about Koa features and API.

examples/framework-koa/package.json

@@ -0,0 +1,24 @@
+{
+  "name": "framework-koa",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "scripts": {
+    "dev": "tsx watch src/index.ts",
+    "build": "tsc",
+    "start": "node dist/index.js"
+  },
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "inngest": "^3.5.0",
+    "koa": "^2.14.2",
+    "koa-bodyparser": "^4.4.1"
+  },
+  "devDependencies": {
+    "@types/koa": "^2.13.11",
+    "@types/koa-bodyparser": "^4.3.12",
+    "tsx": "^4.0.0",
+    "typescript": "^5.2.2"
+  }
+}

examples/framework-koa/src/index.ts

@@ -0,0 +1,20 @@
+import { serve } from "inngest/koa";
+import Koa from "koa";
+import bodyParser from "koa-bodyparser";
+import { functions, inngest } from "./inngest";
+
+const app = new Koa();
+app.use(bodyParser());
+
+const handler = serve({
+  client: inngest,
+  functions,
+});
+
+app.use((ctx) => {
+  if (ctx.request.path === "/api/inngest") {
+    return handler(ctx);
+  }
+});
+
+app.listen(3000);

examples/framework-koa/src/inngest/client.ts

@@ -0,0 +1,4 @@
+import { Inngest } from "inngest";
+import { schemas } from "./types";
+
+export const inngest = new Inngest({ id: "my-koa-app", schemas });

examples/framework-koa/src/inngest/helloWorld.ts

@@ -0,0 +1,11 @@
+import { inngest } from "./client";
+
+export default inngest.createFunction(
+  { id: "hello-world" },
+  { event: "demo/event.sent" },
+  async ({ event, step }) => {
+    return {
+      message: `Hello ${event.name}!`,
+    };
+  }
+);

examples/framework-koa/src/inngest/index.ts

@@ -0,0 +1,5 @@
+import helloWorld from "./helloWorld";
+
+export const functions = [helloWorld];
+
+export { inngest } from "./client";

examples/framework-koa/src/inngest/types.ts

@@ -0,0 +1,10 @@
+import { EventSchemas } from "inngest";
+
+type DemoEventSent = {
+  name: "demo/event.sent";
+  data: {
+    message: string;
+  };
+};
+
+export const schemas = new EventSchemas().fromUnion<DemoEventSent>();

examples/framework-koa/tsconfig.json

@@ -0,0 +1,109 @@
+{
+  "compilerOptions": {
+    /* Visit https://aka.ms/tsconfig to read more about this file */
+
+    /* Projects */
+    // "incremental": true,                              /* Save .tsbuildinfo files to allow for incremental compilation of projects. */
+    // "composite": true,                                /* Enable constraints that allow a TypeScript project to be used with project references. */
+    // "tsBuildInfoFile": "./.tsbuildinfo",              /* Specify the path to .tsbuildinfo incremental compilation file. */
+    // "disableSourceOfProjectReferenceRedirect": true,  /* Disable preferring source files instead of declaration files when referencing composite projects. */
+    // "disableSolutionSearching": true,                 /* Opt a project out of multi-project reference checking when editing. */
+    // "disableReferencedProjectLoad": true,             /* Reduce the number of projects loaded automatically by TypeScript. */
+
+    /* Language and Environment */
+    "target": "es2016" /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */,
+    // "lib": [],                                        /* Specify a set of bundled library declaration files that describe the target runtime environment. */
+    // "jsx": "preserve",                                /* Specify what JSX code is generated. */
+    // "experimentalDecorators": true,                   /* Enable experimental support for legacy experimental decorators. */
+    // "emitDecoratorMetadata": true,                    /* Emit design-type metadata for decorated declarations in source files. */
+    // "jsxFactory": "",                                 /* Specify the JSX factory function used when targeting React JSX emit, e.g. 'React.createElement' or 'h'. */
+    // "jsxFragmentFactory": "",                         /* Specify the JSX Fragment reference used for fragments when targeting React JSX emit e.g. 'React.Fragment' or 'Fragment'. */
+    // "jsxImportSource": "",                            /* Specify module specifier used to import the JSX factory functions when using 'jsx: react-jsx*'. */
+    // "reactNamespace": "",                             /* Specify the object invoked for 'createElement'. This only applies when targeting 'react' JSX emit. */
+    // "noLib": true,                                    /* Disable including any library files, including the default lib.d.ts. */
+    // "useDefineForClassFields": true,                  /* Emit ECMAScript-standard-compliant class fields. */
+    // "moduleDetection": "auto",                        /* Control what method is used to detect module-format JS files. */
+
+    /* Modules */
+    "module": "commonjs" /* Specify what module code is generated. */,
+    "rootDir": "src" /* Specify the root folder within your source files. */,
+    // "moduleResolution": "node10",                     /* Specify how TypeScript looks up a file from a given module specifier. */
+    // "baseUrl": "./",                                  /* Specify the base directory to resolve non-relative module names. */
+    // "paths": {},                                      /* Specify a set of entries that re-map imports to additional lookup locations. */
+    // "rootDirs": [],                                   /* Allow multiple folders to be treated as one when resolving modules. */
+    // "typeRoots": [],                                  /* Specify multiple folders that act like './node_modules/@types'. */
+    // "types": [],                                      /* Specify type package names to be included without being referenced in a source file. */
+    // "allowUmdGlobalAccess": true,                     /* Allow accessing UMD globals from modules. */
+    // "moduleSuffixes": [],                             /* List of file name suffixes to search when resolving a module. */
+    // "allowImportingTsExtensions": true,               /* Allow imports to include TypeScript file extensions. Requires '--moduleResolution bundler' and either '--noEmit' or '--emitDeclarationOnly' to be set. */
+    // "resolvePackageJsonExports": true,                /* Use the package.json 'exports' field when resolving package imports. */
+    // "resolvePackageJsonImports": true,                /* Use the package.json 'imports' field when resolving imports. */
+    // "customConditions": [],                           /* Conditions to set in addition to the resolver-specific defaults when resolving imports. */
+    // "resolveJsonModule": true,                        /* Enable importing .json files. */
+    // "allowArbitraryExtensions": true,                 /* Enable importing files with any extension, provided a declaration file is present. */
+    // "noResolve": true,                                /* Disallow 'import's, 'require's or '<reference>'s from expanding the number of files TypeScript should add to a project. */
+
+    /* JavaScript Support */
+    // "allowJs": true,                                  /* Allow JavaScript files to be a part of your program. Use the 'checkJS' option to get errors from these files. */
+    // "checkJs": true,                                  /* Enable error reporting in type-checked JavaScript files. */
+    // "maxNodeModuleJsDepth": 1,                        /* Specify the maximum folder depth used for checking JavaScript files from 'node_modules'. Only applicable with 'allowJs'. */
+
+    /* Emit */
+    // "declaration": true,                              /* Generate .d.ts files from TypeScript and JavaScript files in your project. */
+    // "declarationMap": true,                           /* Create sourcemaps for d.ts files. */
+    // "emitDeclarationOnly": true,                      /* Only output d.ts files and not JavaScript files. */
+    // "sourceMap": true,                                /* Create source map files for emitted JavaScript files. */
+    // "inlineSourceMap": true,                          /* Include sourcemap files inside the emitted JavaScript. */
+    // "outFile": "./",                                  /* Specify a file that bundles all outputs into one JavaScript file. If 'declaration' is true, also designates a file that bundles all .d.ts output. */
+    "outDir": "dist" /* Specify an output folder for all emitted files. */,
+    // "removeComments": true,                           /* Disable emitting comments. */
+    // "noEmit": true,                                   /* Disable emitting files from a compilation. */
+    // "importHelpers": true,                            /* Allow importing helper functions from tslib once per project, instead of including them per-file. */
+    // "importsNotUsedAsValues": "remove",               /* Specify emit/checking behavior for imports that are only used for types. */
+    // "downlevelIteration": true,                       /* Emit more compliant, but verbose and less performant JavaScript for iteration. */
+    // "sourceRoot": "",                                 /* Specify the root path for debuggers to find the reference source code. */
+    // "mapRoot": "",                                    /* Specify the location where debugger should locate map files instead of generated locations. */
+    // "inlineSources": true,                            /* Include source code in the sourcemaps inside the emitted JavaScript. */
+    // "emitBOM": true,                                  /* Emit a UTF-8 Byte Order Mark (BOM) in the beginning of output files. */
+    // "newLine": "crlf",                                /* Set the newline character for emitting files. */
+    // "stripInternal": true,                            /* Disable emitting declarations that have '@internal' in their JSDoc comments. */
+    // "noEmitHelpers": true,                            /* Disable generating custom helper functions like '__extends' in compiled output. */
+    // "noEmitOnError": true,                            /* Disable emitting files if any type checking errors are reported. */
+    // "preserveConstEnums": true,                       /* Disable erasing 'const enum' declarations in generated code. */
+    // "declarationDir": "./",                           /* Specify the output directory for generated declaration files. */
+    // "preserveValueImports": true,                     /* Preserve unused imported values in the JavaScript output that would otherwise be removed. */
+
+    /* Interop Constraints */
+    // "isolatedModules": true,                          /* Ensure that each file can be safely transpiled without relying on other imports. */
+    // "verbatimModuleSyntax": true,                     /* Do not transform or elide any imports or exports not marked as type-only, ensuring they are written in the output file's format based on the 'module' setting. */
+    // "allowSyntheticDefaultImports": true,             /* Allow 'import x from y' when a module doesn't have a default export. */
+    "esModuleInterop": true /* Emit additional JavaScript to ease support for importing CommonJS modules. This enables 'allowSyntheticDefaultImports' for type compatibility. */,
+    // "preserveSymlinks": true,                         /* Disable resolving symlinks to their realpath. This correlates to the same flag in node. */
+    "forceConsistentCasingInFileNames": true /* Ensure that casing is correct in imports. */,
+
+    /* Type Checking */
+    "strict": true /* Enable all strict type-checking options. */,
+    // "noImplicitAny": true,                            /* Enable error reporting for expressions and declarations with an implied 'any' type. */
+    // "strictNullChecks": true,                         /* When type checking, take into account 'null' and 'undefined'. */
+    // "strictFunctionTypes": true,                      /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */
+    // "strictBindCallApply": true,                      /* Check that the arguments for 'bind', 'call', and 'apply' methods match the original function. */
+    // "strictPropertyInitialization": true,             /* Check for class properties that are declared but not set in the constructor. */
+    // "noImplicitThis": true,                           /* Enable error reporting when 'this' is given the type 'any'. */
+    // "useUnknownInCatchVariables": true,               /* Default catch clause variables as 'unknown' instead of 'any'. */
+    // "alwaysStrict": true,                             /* Ensure 'use strict' is always emitted. */
+    // "noUnusedLocals": true,                           /* Enable error reporting when local variables aren't read. */
+    // "noUnusedParameters": true,                       /* Raise an error when a function parameter isn't read. */
+    // "exactOptionalPropertyTypes": true,               /* Interpret optional property types as written, rather than adding 'undefined'. */
+    // "noImplicitReturns": true,                        /* Enable error reporting for codepaths that do not explicitly return in a function. */
+    // "noFallthroughCasesInSwitch": true,               /* Enable error reporting for fallthrough cases in switch statements. */
+    // "noUncheckedIndexedAccess": true,                 /* Add 'undefined' to a type when accessed using an index. */
+    // "noImplicitOverride": true,                       /* Ensure overriding members in derived classes are marked with an override modifier. */
+    // "noPropertyAccessFromIndexSignature": true,       /* Enforces using indexed accessors for keys declared using an indexed type. */
+    // "allowUnusedLabels": true,                        /* Disable error reporting for unused labels. */
+    // "allowUnreachableCode": true,                     /* Disable error reporting for unreachable code. */
+
+    /* Completeness */
+    // "skipDefaultLibCheck": true,                      /* Skip type checking .d.ts files that are included with TypeScript. */
+    "skipLibCheck": true /* Skip type checking all .d.ts files. */
+  }
+}

packages/inngest/package.json

@@ -65,6 +65,11 @@
       "import": "./h3.js",
       "types": "./h3.d.ts"
     },
+    "./koa": {
+      "require": "./koa.js",
+      "import": "./koa.js",
+      "types": "./koa.d.ts"
+    },
     "./lambda": {
       "require": "./lambda.js",
       "import": "./lambda.js",
@@ -141,6 +146,7 @@
     "@inngest/eslint-plugin-internal": "workspace:^",
     "@jest/globals": "^29.5.0",
     "@microsoft/api-extractor": "^7.33.7",
+    "@shopify/jest-koa-mocks": "^5.1.1",
     "@sveltejs/kit": "^1.27.3",
     "@total-typescript/shoehorn": "^0.1.1",
     "@types/aws-lambda": "^8.10.108",
@@ -149,6 +155,7 @@
     "@types/inquirer": "^9.0.3",
     "@types/jest": "^27.4.1",
     "@types/json-stringify-safe": "^5.0.0",
+    "@types/koa": "^2.13.11",
     "@types/minimist": "^1.2.2",
     "@types/ms": "^0.7.31",
     "@types/node": "^18.16.16",
@@ -166,6 +173,7 @@
     "genversion": "^3.1.1",
     "inquirer": "^9.2.10",
     "jest": "^29.3.1",
+    "koa": "^2.14.2",
     "minimist": "^1.2.8",
     "next": "^13.5.4",
     "nock": "^13.2.9",

packages/inngest/src/cloudflare.test.ts

@@ -60,7 +60,7 @@ testFramework("Cloudflare", CloudflareHandler, {
       },
     ];
   },
-  transformRes: async (res, ret: Response) => {
+  transformRes: async (_args, ret: Response) => {
     const headers: Record<string, string> = {};
 
     ret.headers.forEach((v, k) => {

packages/inngest/src/deno/fresh.test.ts

@@ -68,7 +68,7 @@ testFramework("Deno Fresh", DenoFreshHandler, {
     return [req, env];
   },
 
-  transformRes: async (res, ret: Response) => {
+  transformRes: async (_args, ret: Response) => {
     const headers: Record<string, string> = {};
 
     ret.headers.forEach((v, k) => {

packages/inngest/src/edge.test.ts

@@ -57,7 +57,7 @@ testFramework("Edge", EdgeHandler, {
 
     return [req];
   },
-  transformRes: async (res, ret: Response) => {
+  transformRes: async (_args, ret: Response) => {
     const headers: Record<string, string> = {};
 
     ret.headers.forEach((v, k) => {

packages/inngest/src/koa.test.ts

@@ -0,0 +1,30 @@
+import * as KoaHandler from "@local/koa";
+import { createMockContext } from "@shopify/jest-koa-mocks";
+import { type Dictionary } from "@shopify/jest-koa-mocks/build/ts/create-mock-cookies";
+import { type RequestMethod } from "node-mocks-http";
+import { testFramework } from "./test/helpers";
+
+testFramework("Koa", KoaHandler, {
+  transformReq: (req, _res, _env) => {
+    const ctx = createMockContext({
+      url: `https://${req.headers.host || req.hostname}${req.url}`,
+      method: req.method as RequestMethod,
+      statusCode: req.statusCode,
+      headers: req.headers as Dictionary<string>,
+      host: req.hostname,
+      // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment
+      requestBody: req.body,
+    });
+
+    return [ctx];
+  },
+  transformRes: (args) => {
+    const ctx = args[0] as ReturnType<typeof createMockContext>;
+
+    return Promise.resolve({
+      status: ctx.status,
+      body: ctx.body as string,
+      headers: ctx.response.headers as Record<string, string>,
+    });
+  },
+});