refactor(starter): upgrade and move to typescript

internal/gatsby/on-create-webpack-config.ts

@@ -0,0 +1,25 @@
+import path from "path";
+
+import { CreateWebpackConfigArgs } from "gatsby";
+import { CompilerOptions } from "typescript";
+
+import { compilerOptions } from "../../tsconfig.json";
+
+const onCreateWebpackConfig = (
+  (options: Pick<CompilerOptions, "paths">) =>
+  ({ actions }: CreateWebpackConfigArgs) => {
+    actions.setWebpackConfig({
+      resolve: {
+        alias: Object.entries(options.paths || []).reduce(
+          (aliases, [name, [target]]) => ({
+            ...aliases,
+            [name]: path.resolve(target),
+          }),
+          {},
+        ),
+      },
+    });
+  }
+)(compilerOptions);
+
+export { onCreateWebpackConfig };