StrategyOptionsCallback shouldn't have to pass all SAML options (#838)

Co-authored-by: Chris Barth <chrisjbarth@hotmail.com>

src/types.ts

@@ -36,7 +36,10 @@ export type VerifyWithoutRequest = (profile: Profile | null, done: VerifiedCallb
 
 export type PassportSamlConfig = SamlConfig & StrategyOptions;
 
-export type StrategyOptionsCallback = (err: Error | null, samlOptions?: PassportSamlConfig) => void;
+export type StrategyOptionsCallback = (
+  err: Error | null,
+  samlOptions?: Partial<PassportSamlConfig>
+) => void;
 
 interface BaseMultiStrategyConfig {
   getSamlOptions(req: express.Request, callback: StrategyOptionsCallback): void;

test/multiSamlStrategy.spec.ts

@@ -25,6 +25,15 @@ describe("MultiSamlStrategy()", function () {
     expect(strategy).to.be.an.instanceOf(Strategy);
   });
 
+  it("does not require any properties in the SamlOptionsCallback", function () {
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    const getSamlOptions: StrategyOptionsCallback = (err, samlOptions) => {
+      // do nothing; the return type is void
+    };
+
+    getSamlOptions(null, {});
+  });
+
   it("throws if wrong finder is provided", function () {
     function createStrategy() {
       return new MultiSamlStrategy({} as MultiStrategyConfig, noop, noop);