feat: options.id can be set to Client ID (#107)

Author: gr2m

README.md

@@ -107,10 +107,10 @@ For a complete implementation of GitHub App authentication strategies, see [`@oc
         <code>options.id</code>
       </th>
       <th>
-        <code>number</code>
+        <code>number | string</code>
       </th>
       <td>
-        <strong>Required</strong>. Find <strong>App ID</strong> on the app’s about page in settings.
+        <strong>Required</strong>. The GitHub App's ID or Client ID. For <code>github.com</code> and GHES 3.14+, it is recommended to use the Client ID.
       </td>
     </tr>
     <tr>
@@ -163,7 +163,7 @@ For a complete implementation of GitHub App authentication strategies, see [`@oc
         <code>number</code>
       </th>
       <td>
-        The GitHub App database ID passed in <code>options.id</code>.
+        The GitHub App database ID or Client ID passed in <code>options.id</code>.
       </td>
     </tr>
     <tr>

src/index.ts

@@ -2,11 +2,11 @@ import { getToken } from "./get-token";
 
 import { Options, Result } from "./types";
 
-export async function githubAppJwt({
+export async function githubAppJwt<T extends number | string = number>({
   id,
   privateKey,
   now = Math.floor(Date.now() / 1000),
-}: Options): Promise<Result> {
+}: Options<T>): Promise<Result<T>> {
   // When creating a JSON Web Token, it sets the "issued at time" (iat) to 30s
   // in the past as we have seen people running situations where the GitHub API
   // claimed the iat would be in future. It turned out the clocks on the

src/types.ts

@@ -1,24 +1,23 @@
 export type PrivateKey = string;
-export type AppId = number;
 export type Expiration = number;
 export type Token = string;
 
-export type Options = {
-  id: AppId;
+export type Options<IdType extends number | string = number> = {
+  id: IdType;
   privateKey: PrivateKey;
   now?: number;
 };
 
-export type Result = {
-  appId: AppId;
+export type Result<IdType extends number | string = number> = {
+  appId: IdType;
   expiration: Expiration;
   token: Token;
 };
 
 export type Payload = {
   iat: number;
   exp: number;
-  iss: number;
+  iss: number | string;
 };
 
 export type GetTokenOptions = {

test/node.test.ts

@@ -114,3 +114,14 @@ test("Include the time difference in the expiration and issued_at field", async
   expect(resultPayload.exp).toEqual(580);
   expect(resultPayload.iat).toEqual(-20);
 });
+
+// New test for id set to Client ID
+test("id set to Client ID", async () => {
+  const result = await githubAppJwt({
+    id: "client_id_string",
+    privateKey: PRIVATE_KEY_PKCS8,
+  });
+
+  expect(typeof result.token).toEqual("string");
+  expect(result.appId).toEqual("client_id_string");
+});