feat: expose TOKEN_ERROR_CODES and derive duplicated error code types from it (#573)

* feat: expose TOKEN_ERROR_CODES and derive duplicated error code types from it

* chore: avoid repeating error codes in TokenError class declaration

* test: validate TOKEN_ERROR_CODES is a record of TokenValidationErrorCodes

* test: additional type tests

* test: fix typo

* test: do not check each key individually

* test: additional type tests

Author: wopian

src/index.d.ts

@@ -14,47 +14,12 @@ export type Algorithm =
   | 'PS512'
   | 'EdDSA'
 
-export type TokenValidationErrorCode =
-  | 'FAST_JWT_INVALID_TYPE'
-  | 'FAST_JWT_INVALID_OPTION'
-  | 'FAST_JWT_INVALID_ALGORITHM'
-  | 'FAST_JWT_INVALID_CLAIM_TYPE'
-  | 'FAST_JWT_INVALID_CLAIM_VALUE'
-  | 'FAST_JWT_INVALID_KEY'
-  | 'FAST_JWT_INVALID_SIGNATURE'
-  | 'FAST_JWT_INVALID_PAYLOAD'
-  | 'FAST_JWT_MALFORMED'
-  | 'FAST_JWT_INACTIVE'
-  | 'FAST_JWT_EXPIRED'
-  | 'FAST_JWT_MISSING_KEY'
-  | 'FAST_JWT_KEY_FETCHING_ERROR'
-  | 'FAST_JWT_SIGN_ERROR'
-  | 'FAST_JWT_VERIFY_ERROR'
-  | 'FAST_JWT_MISSING_REQUIRED_CLAIM'
-  | 'FAST_JWT_MISSING_SIGNATURE'
+export type TokenValidationErrorCode = typeof TOKEN_ERROR_CODES[keyof typeof TOKEN_ERROR_CODES]
 
 declare class TokenError extends Error {
   constructor(code: TokenValidationErrorCode, message?: string, additional?: { [key: string]: any });
   static wrap(originalError: Error, code: TokenValidationErrorCode, message: string): TokenError
-  static codes: {
-    invalidType: 'FAST_JWT_INVALID_TYPE'
-    invalidOption: 'FAST_JWT_INVALID_OPTION'
-    invalidAlgorithm: 'FAST_JWT_INVALID_ALGORITHM'
-    invalidClaimType: 'FAST_JWT_INVALID_CLAIM_TYPE'
-    invalidClaimValue: 'FAST_JWT_INVALID_CLAIM_VALUE'
-    invalidKey: 'FAST_JWT_INVALID_KEY'
-    invalidSignature: 'FAST_JWT_INVALID_SIGNATURE'
-    invalidPayload: 'FAST_JWT_INVALID_PAYLOAD'
-    malformed: 'FAST_JWT_MALFORMED'
-    inactive: 'FAST_JWT_INACTIVE'
-    expired: 'FAST_JWT_EXPIRED'
-    missingKey: 'FAST_JWT_MISSING_KEY'
-    keyFetchingError: 'FAST_JWT_KEY_FETCHING_ERROR'
-    signError: 'FAST_JWT_SIGN_ERROR'
-    verifyError: 'FAST_JWT_VERIFY_ERROR'
-    missingRequiredClaim: 'FAST_JWT_MISSING_REQUIRED_CLAIM'
-    missingSignature: 'FAST_JWT_MISSING_SIGNATURE'
-  }
+  static codes: typeof TOKEN_ERROR_CODES
 
   code: TokenValidationErrorCode;
   [key: string]: any
@@ -149,6 +114,26 @@ export interface PrivateKey {
   passphrase: string | undefined
 }
 
+export const TOKEN_ERROR_CODES: {
+  readonly invalidType: 'FAST_JWT_INVALID_TYPE';
+  readonly invalidOption: 'FAST_JWT_INVALID_OPTION';
+  readonly invalidAlgorithm: 'FAST_JWT_INVALID_ALGORITHM';
+  readonly invalidClaimType: 'FAST_JWT_INVALID_CLAIM_TYPE';
+  readonly invalidClaimValue: 'FAST_JWT_INVALID_CLAIM_VALUE';
+  readonly invalidKey: 'FAST_JWT_INVALID_KEY';
+  readonly invalidSignature: 'FAST_JWT_INVALID_SIGNATURE';
+  readonly invalidPayload: 'FAST_JWT_INVALID_PAYLOAD';
+  readonly malformed: 'FAST_JWT_MALFORMED';
+  readonly inactive: 'FAST_JWT_INACTIVE';
+  readonly expired: 'FAST_JWT_EXPIRED';
+  readonly missingKey: 'FAST_JWT_MISSING_KEY';
+  readonly keyFetchingError: 'FAST_JWT_KEY_FETCHING_ERROR';
+  readonly signError: 'FAST_JWT_SIGN_ERROR';
+  readonly verifyError: 'FAST_JWT_VERIFY_ERROR';
+  readonly missingRequiredClaim: 'FAST_JWT_MISSING_REQUIRED_CLAIM';
+  readonly missingSignature: 'FAST_JWT_MISSING_SIGNATURE';
+};
+
 export function createSigner<T = SignerPayload>(
   options?: Partial<SignerOptions & { key: Bufferable | PrivateKey }>
 ): typeof SignerSync<T>

test/types.spec.ts

@@ -9,7 +9,8 @@ import {
   DecodedJwt,
   JwtHeader,
   TokenError,
-  TokenValidationErrorCode
+  TokenValidationErrorCode,
+  TOKEN_ERROR_CODES
 } from '..'
 
 // Signing
@@ -171,9 +172,18 @@ const signerOptionsNoAlg = {
 }
 expectNotAssignable<JwtHeader>(signerOptionsNoAlg.header)
 
-// Check all errors are typed correctly
+// Check object and class static matches their own type
+expectType<typeof TOKEN_ERROR_CODES>(TOKEN_ERROR_CODES)
+expectType<typeof TOKEN_ERROR_CODES>(TokenError.codes)
+
+// Check all enum values are assignable to TokenValidationErrorCode union
+expectType<TokenValidationErrorCode[]>(Object.values(TOKEN_ERROR_CODES))
 expectType<TokenValidationErrorCode[]>(Object.values(TokenError.codes))
 
+// Check enums resolve to correct string literals
+const code: TokenValidationErrorCode = TOKEN_ERROR_CODES.expired
+expectType<"FAST_JWT_EXPIRED">(code)
+
 const decodedJwt: DecodedJwt = {
   header: { alg: 'RS256', typ: 'JWT' },
   payload: { sub: '12345', iss: 'iss' },