Work around limitations of TypeScript’s “instanceof” for Errors

Author: AJCStriker

package.json

@@ -1,6 +1,6 @@
 {
   "name": "strontium",
-  "version": "2.2.3",
+  "version": "2.2.4",
   "description": "Strontium is a TypeScript toolkit for High Performance API servers built for Production not Projects.",
   "main": "lib/src/index.js",
   "types": "lib/src/index.d.ts",

src/errors/http/HTTPError.ts

@@ -17,4 +17,12 @@ export abstract class HTTPError extends StrontiumError {
             errorMessage: this.externalMessage,
         }
     }
+
+    public static isHTTPError(e: any): e is HTTPError {
+        return (
+            e !== undefined &&
+            typeof e.statusCode === "number" &&
+            typeof e.toResponseBody === "function"
+        )
+    }
 }

src/http/drivers/FastifyServer.ts

@@ -189,7 +189,7 @@ export class FastifyServer implements Process {
             } catch (e) {
                 // Detect Input Validation issues.
                 // Any other errors will be thrown directly if they are HTTPError compatible or 500 and logged if not.
-                if (e instanceof HTTPError) {
+                if (HTTPError.isHTTPError(e)) {
                     response.code(e.statusCode)
                     return e.toResponseBody()
                 } else {