Merge pull request #75 from ty-ras/issue/73-add-more-code

#73 Adding also the error class.

code/data-frontend/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@ty-ras/data-frontend",
-  "version": "2.1.0",
+  "version": "2.1.1",
   "author": {
     "name": "Stanislav Muhametsin",
     "email": "[email protected]",

code/data-frontend/src/__test__/clients-errors.spec.ts

@@ -0,0 +1,12 @@
+/**
+ * @file This file contains tests for file `../clients-errors.ts`.
+ */
+
+import test from "ava";
+import * as spec from "../clients-errors";
+
+test("Validate that isNon2xxStatusCodeError method works", (c) => {
+  c.plan(2);
+  c.true(spec.isNon2xxStatusCodeError(new spec.Non2xxStatusCodeError(999)));
+  c.false(spec.isNon2xxStatusCodeError(new Error()));
+});

code/data-frontend/src/clients-errors.ts

@@ -0,0 +1,26 @@
+/**
+ * @file This file contains functionality related to errors tha can be thrown during sending the request and receiving response to HTTP backend.
+ */
+
+/**
+ * This error is thrown when the backend returns something else than `200` or `204` as status code.
+ * Notice that only type information about this is exported, not the class itself.
+ */
+export class Non2xxStatusCodeError extends Error {
+  /**
+   * Creates new instance of this error with given parameters.
+   * @param statusCode The status code returned by backend.
+   */
+  public constructor(public readonly statusCode: number) {
+    super(`Status code ${statusCode} was returned.`);
+  }
+}
+
+/**
+ * Helper function to test whether some error is {@link Non2xxStatusCodeError}.
+ * @param error The {@link Error} to test.
+ * @returns `true` if given `error` is {@link Non2xxStatusCodeError}, `false` otherwise.
+ */
+export const isNon2xxStatusCodeError = (
+  error: unknown,
+): error is Non2xxStatusCodeError => error instanceof Non2xxStatusCodeError;

code/data-frontend/src/index.ts

@@ -8,3 +8,4 @@ export * from "./api-call-factory-factory";
 export * from "./errors";
 export * from "./url";
 export * from "./clients";
+export * from "./clients-errors";