Merge pull request #2 from hayd/error-visibility

Throw a readable error when baseFetch fails

mod.ts

@@ -134,26 +134,21 @@ function createCache(conf: Doc): Doc {
 }
 
 /** Base fetch. */
-function baseFetch(conf: Doc, op: string, params: Doc): Promise<Doc> {
+async function baseFetch(conf: Doc, op: string, params: Doc): Promise<Doc> {
   const payload: Uint8Array = encode(JSON.stringify(params), "utf8");
 
   const headers: Headers = createHeaders(op, payload, conf as HeadersConfig);
 
-  return fetch(conf.endpoint, {
+  const response: Response = await fetch(conf.endpoint, {
     method: conf.method,
     headers,
     body: payload
-  }).then(
-    (response: Response): Doc => {
-      if (!response.ok) {
-        throw new Error(
-          `http query request failed: ${response.status} ${response.statusText}`
-        );
-      }
-
-      return response.json();
-    }
-  );
+  });
+  const body = await response.json();
+  if (!response.ok) {
+    throw new Error(body.message);
+  }
+  return body;
 }
 
 /** Base op. */

test.ts

@@ -1,5 +1,9 @@
 import { test, runIfMain } from "https://deno.land/std/testing/mod.ts";
-import { assert, assertEquals } from "https://deno.land/std/testing/asserts.ts";
+import {
+  assert,
+  assertEquals,
+  assertThrowsAsync
+} from "https://deno.land/std/testing/asserts.ts";
 import { encode } from "https://denopkg.com/chiefbiiko/std-encoding/mod.ts";
 import { awsSignatureV4, kdf } from "./client/mod.ts";
 import { ClientConfig, DynamoDBClient, createClient } from "./mod.ts";
@@ -403,4 +407,29 @@ test({
   }
 });
 
+test({
+  name: "missing table throws a readable error",
+  async fn(): Promise<void> {
+    const ddbc: DynamoDBClient = createClient(CONF);
+
+    let result: Doc = await ddbc.listTables();
+
+    if (result.TableNames.includes("nonexistent_table")) {
+      await ddbc.deleteTable({
+        TableName: "nonexistent_table"
+      });
+    }
+
+    async function fn(): Promise<void> {
+      await ddbc.scan({ TableName: "nonexistent_table" });
+    }
+
+    assertThrowsAsync(
+      fn,
+      Error,
+      "Cannot do operations on a non-existent table"
+    );
+  }
+});
+
 runIfMain(import.meta);