address review comments

Author: LekoArts

docs/docs/how-to/custom-configuration/typescript.md

@@ -253,6 +253,7 @@ exports.createPages = () => {}
 
 Gatsby natively supports JavaScript and TypeScript, you can change files from `.js`/`.jsx` to `.ts`/ `tsx` at any point to start adding types and gaining the benefits of a type system. But you'll need to do a bit more to be able use Typescipt in `gatsby-*` files:
 
+- Run `gatsby clean` to remove any old artifacts
 - Convert your `.js`/`.jsx` files to `.ts/.tsx`
 - Install `@types/node`, `@types/react`, `@types/react-dom`, `typescript` as `devDependencies`
 - Add a `tsconfig.json` file using `npx tsc init` or use the one from [gatsby-minimal-starter-ts](https://github.com/gatsbyjs/gatsby/blob/master/starters/gatsby-starter-minimal-ts/tsconfig.json)

packages/gatsby-cli/src/structured-errors/error-map.ts

@@ -698,6 +698,13 @@ const errors = {
     type: Type.COMPILATION,
     category: ErrorCategory.USER,
   },
+  "11903": {
+    text: (context): string =>
+      `There was an unhandled error during compilation for ${context.siteRoot}. Please run the command with the --verbose flag again.`,
+    level: Level.ERROR,
+    type: Type.COMPILATION,
+    category: ErrorCategory.USER,
+  },
 }
 
 export type ErrorId = string | keyof typeof errors

packages/gatsby/src/services/initialize.ts

@@ -330,7 +330,7 @@ export async function initialize({
     `${program.directory}/gatsby-node.js`,
     `${program.directory}/gatsby-config.ts`,
     `${program.directory}/gatsby-node.ts`,
-  ].filter(Boolean) as Array<string>
+  ] as Array<string>
 
   const state = store.getState()
 

packages/gatsby/src/utils/parcel/compile-gatsby-files.ts

@@ -48,7 +48,17 @@ export async function compileGatsbyFiles(siteRoot: string): Promise<void> {
     await emptyDir(distDir)
     await parcel.run()
   } catch (error) {
-    handleErrors(error.diagnostics)
+    if (error.diagnostics) {
+      handleErrors(error.diagnostics)
+    } else {
+      reporter.panic({
+        id: `11903`,
+        error,
+        context: {
+          siteRoot,
+        },
+      })
+    }
   }
 }