Optional generic types for Payload (#84)

algorithm.ts

@@ -17,8 +17,8 @@ export type Algorithm =
   | "RS512"
   | "ES256"
   | "ES384"
-  // | "ES512" //is not yet supported.
   // https://github.com/denoland/deno/blob/main/ext/crypto/00_crypto.js
+  // | "ES512" //is not yet supported.
   | "none";
 
 // Still needs an 'any' type! Does anyone have an idea?

deps.ts

@@ -1 +1 @@
-export * as base64url from "https://deno.land/std@0.204.0/encoding/base64url.ts";
+export * as base64url from "https://deno.land/std@0.205.0/encoding/base64url.ts";

dist/mod.js

@@ -396,12 +396,16 @@ function createSigningInput(header, payload) {
     return `${mod.encode(encoder1.encode(JSON.stringify(header)))}.${mod.encode(encoder1.encode(JSON.stringify(payload)))}`;
 }
 async function create1(header, payload, key) {
-    if (verify(header.alg, key)) {
-        const signingInput = createSigningInput(header, payload);
-        const signature = await create(header.alg, key, signingInput);
-        return `${signingInput}.${signature}`;
+    if (isObject(payload)) {
+        if (verify(header.alg, key)) {
+            const signingInput = createSigningInput(header, payload);
+            const signature = await create(header.alg, key, signingInput);
+            return `${signingInput}.${signature}`;
+        } else {
+            throw new Error(`The jwt's alg '${header.alg}' does not match the key's algorithm.`);
+        }
     } else {
-        throw new Error(`The jwt's alg '${header.alg}' does not match the key's algorithm.`);
+        throw new Error(`The jwt claims set is not a JSON object.`);
     }
 }
 function getNumericDate(exp) {

examples/deps.ts

@@ -1,2 +1 @@
-export { serve } from "https://deno.land/std@0.140.0/http/server.ts";
-export * as base64 from "https://deno.land/std@0.140.0/encoding/base64.ts";
+export * as base64 from "https://deno.land/std@0.205.0/encoding/base64.ts";

examples/hs512.ts

@@ -1,7 +1,10 @@
-import { create, getNumericDate, verify } from "../mod.ts";
-import { serve } from "./deps.ts";
-
-import type { Header, Payload } from "../mod.ts";
+import {
+  create,
+  getNumericDate,
+  type Header,
+  type Payload,
+  verify,
+} from "../mod.ts";
 
 const key = await crypto.subtle.generateKey(
   { name: "HMAC", hash: "SHA-512" },
@@ -31,4 +34,4 @@ async function handleRequest(request: Request) {
   }
 }
 
-await serve(handleRequest);
+Deno.serve(handleRequest);

examples/rs384.ts

@@ -1,7 +1,4 @@
-import { create, verify } from "../mod.ts";
-import { serve } from "./deps.ts";
-
-import type { Header, Payload } from "../mod.ts";
+import { create, type Header, type Payload, verify } from "../mod.ts";
 
 const { privateKey, publicKey } = await window.crypto.subtle.generateKey(
   {
@@ -39,4 +36,4 @@ async function handleRequest(request: Request) {
   }
 }
 
-await serve(handleRequest);
+Deno.serve(handleRequest);

mod.ts

@@ -142,9 +142,9 @@ function validateAudClaim(
  * jwt has a valid _serialization_. Otherwise it throws an `Error`. This function
  * does **not** verify the digital signature.
  */
-export function decode(
+export function decode<PayloadType extends Payload | unknown = unknown>(
   jwt: string,
-): [header: unknown, payload: unknown, signature: Uint8Array] {
+): [unknown, PayloadType, Uint8Array] {
   try {
     const arr = jwt
       .split(".")
@@ -154,7 +154,7 @@ export function decode(
           ? JSON.parse(decoder.decode(uint8Array))
           : uint8Array
       );
-    if (is3Tuple(arr)) return arr;
+    if (is3Tuple(arr)) return arr as [unknown, PayloadType, Uint8Array];
     else throw new Error();
   } catch {
     throw Error("The serialization of the jwt is invalid.");
@@ -200,11 +200,11 @@ export function validate(
  * Takes jwt, `CryptoKey` and `VerifyOptions` and returns the `Payload` of the
  * jwt if the jwt is valid. Otherwise it throws an `Error`.
  */
-export async function verify(
+export async function verify<PayloadType extends Payload>(
   jwt: string,
   key: CryptoKey | null,
   options?: VerifyOptions,
-): Promise<Payload> {
+): Promise<PayloadType> {
   const { header, payload, signature } = validate(decode(jwt), options);
   if (verifyAlgorithm(header.alg, key)) {
     if (
@@ -223,7 +223,7 @@ export async function verify(
       throw new Error("The payload does not satisfy all passed predicates.");
     }
 
-    return payload;
+    return payload as PayloadType;
   } else {
     throw new Error(
       `The jwt's alg '${header.alg}' does not match the key's algorithm.`,
@@ -255,15 +255,19 @@ export async function create(
   payload: Payload,
   key: CryptoKey | null,
 ): Promise<string> {
-  if (verifyAlgorithm(header.alg, key)) {
-    const signingInput = createSigningInput(header, payload);
-    const signature = await createSignature(header.alg, key, signingInput);
+  if (isObject(payload)) {
+    if (verifyAlgorithm(header.alg, key)) {
+      const signingInput = createSigningInput(header, payload);
+      const signature = await createSignature(header.alg, key, signingInput);
 
-    return `${signingInput}.${signature}`;
+      return `${signingInput}.${signature}`;
+    } else {
+      throw new Error(
+        `The jwt's alg '${header.alg}' does not match the key's algorithm.`,
+      );
+    }
   } else {
-    throw new Error(
-      `The jwt's alg '${header.alg}' does not match the key's algorithm.`,
-    );
+    throw new Error(`The jwt claims set is not a JSON object.`);
   }
 }
 

tests/test.ts

@@ -174,6 +174,13 @@ Deno.test({
       Error,
       "The jwt's alg 'HS256' does not match the key's algorithm.",
     );
+    await assertRejects(
+      async () => {
+        await create(header, "invalid payload" as unknown as Payload, keyHS512);
+      },
+      Error,
+      "The jwt claims set is not a JSON object.",
+    );
   },
 });
 
@@ -222,6 +229,19 @@ Deno.test({
       { exp: 0 },
     );
 
+    await assertEquals(
+      (await verify<{ email: string }>(
+        await create(
+          { alg: "HS512", typ: "JWT" },
+          { email: "joe@example.com" },
+          keyHS512,
+        ),
+        keyHS512,
+        { ignoreExp: true },
+      )).email,
+      "joe@example.com",
+    );
+
     await assertEquals(
       await verify(
         await create(

tests/test_deps.ts

@@ -2,8 +2,8 @@ export {
   assertEquals,
   assertRejects,
   assertThrows,
-} from "https://deno.land/std@0.204.0/testing/asserts.ts";
+} from "https://deno.land/std@0.205.0/testing/asserts.ts";
 
 export {
   decode as decodeHex,
-} from "https://deno.land/std@0.204.0/encoding/hex.ts";
+} from "https://deno.land/std@0.205.0/encoding/hex.ts";