warn if the serialize function isn't there/valid

gatsbyjs · Feb 10, 2021 · 27bc3c7 · 27bc3c7
1 parent 07ebe2c
commit 27bc3c7
Showing 1 changed file with 20 additions and 14 deletions.
diff --git a/packages/gatsby-plugin-feed/src/gatsby-node.js b/packages/gatsby-plugin-feed/src/gatsby-node.js
@@ -23,7 +23,7 @@ const serialize = ({ query: { site, allMarkdownRemark } }) =>
     }
   })
 
-exports.onPostBuild = async ({ graphql }, pluginOptions) => {
+exports.onPostBuild = async ({ graphql }, pluginOptions, reporter) => {
   /*
    * Run the site settings query to gather context, then
    * then run the corresponding feed for each query.
@@ -47,21 +47,27 @@ exports.onPostBuild = async ({ graphql }, pluginOptions) => {
       ...feed,
     }
 
-    const serializer =
-      feed.serialize && typeof feed.serialize === `function`
-        ? feed.serialize
-        : serialize
+    if (!feed.serialize || typeof feed.serialize !== `function`) {
+      reporter.warn(
+        `You did not pass in a valid serialize function. Your feed will not be generated.`
+      )
+    } else {
+      const serializer =
+        feed.serialize && typeof feed.serialize === `function`
+          ? feed.serialize
+          : serialize
 
-    const rssFeed = (await serializer(locals)).reduce((merged, item) => {
-      merged.item(item)
-      return merged
-    }, new RSS(setup(locals)))
+      const rssFeed = (await serializer(locals)).reduce((merged, item) => {
+        merged.item(item)
+        return merged
+      }, new RSS(setup(locals)))
 
-    const outputPath = path.join(publicPath, feed.output)
-    const outputDir = path.dirname(outputPath)
-    if (!(await fs.exists(outputDir))) {
-      await fs.mkdirp(outputDir)
+      const outputPath = path.join(publicPath, feed.output)
+      const outputDir = path.dirname(outputPath)
+      if (!(await fs.exists(outputDir))) {
+        await fs.mkdirp(outputDir)
+      }
+      await fs.writeFile(outputPath, rssFeed.xml())
     }
-    await fs.writeFile(outputPath, rssFeed.xml())
   }
 }