fix(types): Origin within OriginFunction can be undefined (#237)

* Callback of origin should be potentially undefined

In reference to #236 origin cannot be assumed to always be a string. Propose making it `string | undefined` to ensure people handle it correctly. This would flag quickly in the sync example on the README that new URL can't work with undefined.

* Update index.d.ts

Co-authored-by: KaKa <climba03003@gmail.com>

* restructure, add typings test

Co-authored-by: KaKa <climba03003@gmail.com>
Co-authored-by: Uzlopak <aras.abbasi@googlemail.com>

package.json

@@ -3,17 +3,14 @@
   "version": "8.2.0",
   "description": "Fastify CORS",
   "main": "index.js",
-  "types": "index.d.ts",
+  "types": "types/index.d.ts",
   "scripts": {
     "coverage": "tap --cov --coverage-report=html test",
-    "lint": "npm run lint:standard && npm run lint:typescript",
+    "lint": "standard",
     "lint:fix": "standard --fix",
-    "lint:standard": "standard",
-    "lint:typescript": "standard --parser @typescript-eslint/parser --plugin @typescript-eslint/eslint-plugin test/*.ts",
-    "test": "npm run unit && npm run typescript",
-    "test:ci": "npm run lint && tap test/*.test.js --coverage-report=lcovonly && npm run typescript",
-    "typescript": "tsd",
-    "unit": "tap test/*.test.js"
+    "test": "npm run test:unit && npm run test:typescript",
+    "test:typescript": "tsd",
+    "test:unit": "tap test/*.test.js"
   },
   "keywords": [
     "fastify",

index.d.ts → types/index.d.ts

@@ -22,7 +22,7 @@ type FastifyCorsHook =
   | 'onSend'
 
 declare namespace fastifyCors {
-  export type OriginFunction = (origin: string, callback: OriginCallback) => void;
+  export type OriginFunction = (origin: string | undefined, callback: OriginCallback) => void;
 
   export interface FastifyCorsOptions {
     /**

test/index.test-d.ts → types/index.test-d.ts

@@ -1,4 +1,5 @@
 import fastify from 'fastify'
+import { expectType } from 'tsd'
 import fastifyCors, {
   FastifyCorsOptionsDelegate,
   FastifyCorsOptionsDelegatePromise,
@@ -310,3 +311,10 @@ appHttp2.register(fastifyCors, {
 })
 
 appHttp2.register(fastifyCors, delegate)
+
+appHttp2.register(fastifyCors, {
+  hook: 'preParsing',
+  origin: function (origin) {
+    expectType<string|undefined>(origin)
+  },
+})