feat(plugin): Log the URL that caused a failure (#102)

* feat: log the URL that caused a failure.

The added context is very helpful.

* Update index.js

* Add tests

* Update src/index.js

Co-Authored-By: Michal Piechowiak <misiek.piechowiak@gmail.com>

* Update index.js

* Update index.js

* Update tests

Co-authored-by: Michaël De Boey <info@michaeldeboey.be>
Co-authored-by: Michal Piechowiak <misiek.piechowiak@gmail.com>

Author: 3 people

src/__tests__/__fixtures__/ErrorTransformer.md

@@ -0,0 +1 @@
+https://error-site.com

src/__tests__/plugin.js

@@ -69,4 +69,23 @@ describe('gatsby-remark-embedder', () => {
       "
     `);
   });
+
+  test('logs when a transformer errors', async () => {
+    const errorTransformer = {
+      getHTML: () => {
+        throw new Error('An error occurred in ErrorTransformer');
+      },
+      shouldTransform: () => true,
+    };
+
+    const markdownAST = getMarkdownASTForFile('ErrorTransformer', true);
+
+    await expect(
+      plugin({ cache, markdownAST }, { customTransformers: [errorTransformer] })
+    ).rejects.toMatchInlineSnapshot(`
+[Error: The following error appeared while processing 'https://error-site.com/':
+
+An error occurred in ErrorTransformer]
+`);
+  });
 });

src/index.js

@@ -48,16 +48,22 @@ export default async (
       .filter(({ shouldTransform }) => shouldTransform(urlString))
       .forEach(({ getHTML }) => {
         transformations.push(async () => {
-          let html = await cache.get(urlString);
+          try {
+            let html = await cache.get(urlString);
 
-          if (!html) {
-            html = await getHTML(urlString);
-            await cache.set(urlString, html);
-          }
+            if (!html) {
+              html = await getHTML(urlString);
+              await cache.set(urlString, html);
+            }
+
+            node.type = `html`;
+            node.value = html;
+            node.children = undefined;
+          } catch (error) {
+            error.message = `The following error appeared while processing '${urlString}':\n\n${error.message}`;
 
-          node.type = `html`;
-          node.value = html;
-          node.children = undefined;
+            throw error;
+          }
         });
       });
   });