types: check error argument type

types/index.d.ts

@@ -1,5 +1,23 @@
-declare function createError<C extends string, SC extends number> (code: C, message: string, statusCode: SC, Base?: Error): createError.FastifyErrorConstructor<{ code: C, statusCode: SC }>
-declare function createError<C extends string> (code: C, message: string, statusCode?: number, Base?: Error): createError.FastifyErrorConstructor<{ code: C }>
+declare function createError<C extends string, SC extends number, Arg extends unknown[] = [any?, any?, any?]> (
+  code: C,
+  message: string,
+  statusCode: SC,
+  Base?: Error
+): createError.FastifyErrorConstructor<{ code: C, statusCode: SC }, Arg>
+
+declare function createError<C extends string, Arg extends unknown[] = [any?, any?, any?]> (
+  code: C,
+  message: string,
+  statusCode?: number,
+  Base?: Error
+): createError.FastifyErrorConstructor<{ code: C }, Arg>
+
+declare function createError<Arg extends unknown[] = [any?, any?, any?]> (
+  code: string,
+  message: string,
+  statusCode?: number,
+  Base?: Error
+): createError.FastifyErrorConstructor<{ code: string }, Arg>
 
 type CreateError = typeof createError
 
@@ -10,9 +28,12 @@ declare namespace createError {
     statusCode?: number
   }
 
-  export interface FastifyErrorConstructor<E extends { code: string, statusCode?: number } = { code: string, statusCode?: number }> {
-    new (a?: any, b?: any, c?: any): FastifyError & E
-    (a?: any, b?: any, c?: any): FastifyError & E
+  export interface FastifyErrorConstructor<
+    E extends { code: string, statusCode?: number } = { code: string, statusCode?: number },
+    T extends unknown[] = [any?, any?, any?]
+  > {
+    new(...arg: T): FastifyError & E
+    (...arg: T): FastifyError & E
     readonly prototype: FastifyError & E
   }
 

types/index.test-d.ts

@@ -1,5 +1,5 @@
 import createError, { FastifyError, FastifyErrorConstructor } from '..'
-import { expectType } from 'tsd'
+import { expectType, expectError } from 'tsd'
 
 const CustomError = createError('ERROR_CODE', 'message')
 expectType<FastifyErrorConstructor<{ code: 'ERROR_CODE' }>>(CustomError)
@@ -16,3 +16,52 @@ expectType<FastifyError & { code: 'OTHER_CODE', statusCode: 400 }>(typed)
 expectType<'OTHER_CODE'>(typed.code)
 expectType<string>(typed.message)
 expectType<400>(typed.statusCode)
+
+/* eslint-disable no-new */
+const CustomTypedArgError = createError<[string]>('OTHER_CODE', 'expect %s message', 400)
+CustomTypedArgError('a')
+expectError(CustomTypedArgError('a', 'b'))
+expectError(new CustomTypedArgError('a', 'b'))
+expectError(CustomTypedArgError(1))
+expectError(new CustomTypedArgError(1))
+
+const CustomTypedArgError2 = createError<string, number, [string]>('OTHER_CODE', 'expect %s message', 400)
+CustomTypedArgError2('a')
+expectError(CustomTypedArgError2('a', 'b'))
+expectError(new CustomTypedArgError2('a', 'b'))
+expectError(CustomTypedArgError2(1))
+expectError(new CustomTypedArgError2(1))
+
+const CustomTypedArgError3 = createError<string, number, [string, string]>('OTHER_CODE', 'expect %s message but got %s', 400)
+expectError(CustomTypedArgError3('a'))
+CustomTypedArgError3('a', 'b')
+new CustomTypedArgError3('a', 'b')
+expectError(CustomTypedArgError3(1))
+expectError(new CustomTypedArgError3(1))
+expectError(new CustomTypedArgError3(1, 2))
+expectError(new CustomTypedArgError3('1', 2))
+expectError(new CustomTypedArgError3(1, '2'))
+
+const CustomTypedArgError4 = createError<string, number, [string, string]>('OTHER_CODE', 'expect %s message but got %s', 400)
+expectError(CustomTypedArgError4('a'))
+CustomTypedArgError4('a', 'b')
+new CustomTypedArgError4('a', 'b')
+expectError(CustomTypedArgError4(1))
+expectError(new CustomTypedArgError4(1))
+expectError(new CustomTypedArgError4(1, 2))
+expectError(new CustomTypedArgError4('1', 2))
+expectError(new CustomTypedArgError4(1, '2'))
+
+const CustomTypedArgError5 = createError<[string, string, string, string]>('OTHER_CODE', 'expect %s message but got %s. Please contact %s by emailing to %s', 400)
+expectError(CustomTypedArgError5('a'))
+expectError(new CustomTypedArgError5('a', 'b'))
+expectError(new CustomTypedArgError5('a', 'b', 'c'))
+CustomTypedArgError5('a', 'b', 'c', 'd')
+expectError(new CustomTypedArgError5('a', 'b', 'c', 'd', 'e'))
+
+const CustomTypedArgError6 = createError<string, number, [string, string, string, string]>('OTHER_CODE', 'expect %s message but got %s. Please contact %s by emailing to %s', 400)
+expectError(CustomTypedArgError6('a'))
+expectError(new CustomTypedArgError6('a', 'b'))
+expectError(new CustomTypedArgError6('a', 'b', 'c'))
+CustomTypedArgError6('a', 'b', 'c', 'd')
+expectError(new CustomTypedArgError6('a', 'b', 'c', 'd', 'e'))