added error page

Author: davidsklar99

pages/_error/+Page.client.ts

@@ -0,0 +1,31 @@
+// /pages/_error/+Page.ts
+  
+import { h } from '@macrostrat/map-interface'
+import { usePageContext } from 'vike-react/usePageContext'
+
+export function Page() {
+  const pageContext = usePageContext()
+ 
+  let msg: string // Message shown to the user
+  const { abortReason, abortStatusCode } = pageContext
+  if (abortReason?.notAdmin) {
+    // Handle `throw render(403, { notAdmin: true })`
+    msg = "You cannot access this page because you aren't an administrator."
+  } else if (typeof abortReason === 'string') {
+    // Handle `throw render(abortStatusCode, `You cannot access ${someCustomMessage}`)`
+    msg = abortReason
+  } else if (abortStatusCode === 403) {
+    // Handle `throw render(403)`
+    msg = "You cannot access this page because you don't have enough privileges."
+  } else if (abortStatusCode === 401) {
+    // Handle `throw render(401)`
+    msg = "You cannot access this page because you aren't logged in. Please log in."
+  } else {
+    // Fallback error message
+    msg = pageContext.is404 ?
+      "This page doesn't exist." :
+      "Something went wrong. Try again (later)."
+  }
+
+  return h('h1', msg)
+}