fix(Deno.ppid): improve error message when --unstable is missing (#6717)

cli/js/diagnostics_util.ts

@@ -64,20 +64,43 @@ const unstableDenoGlobalProperties = [
   "Permissions",
   "PermissionStatus",
   "hostname",
+  "ppid",
 ];
 
 function transformMessageText(messageText: string, code: number): string {
-  if (code === 2339) {
+  switch (code) {
-    const property = messageText
+    case 2339: {
-      .replace(/^Property '/, "")
+      const property = messageText
-      .replace(/' does not exist on type 'typeof Deno'\.$/, "");
+        .replace(/^Property '/, "")
-    if (
+        .replace(/' does not exist on type 'typeof Deno'\./, "");
-      messageText.endsWith("on type 'typeof Deno'.") &&
+
-      unstableDenoGlobalProperties.includes(property)
+      if (
-    ) {
+        messageText.endsWith("on type 'typeof Deno'.") &&
-      return `${messageText} 'Deno.${property}' is an unstable API. Did you forget to run with the '--unstable' flag?`;
+        unstableDenoGlobalProperties.includes(property)
+      ) {
+        return `${messageText} 'Deno.${property}' is an unstable API. Did you forget to run with the '--unstable' flag?`;
+      }
+      break;
+    }
+    case 2551: {
+      const suggestionMessagePattern = / Did you mean '(.+)'\?$/;
+      const property = messageText
+        .replace(/^Property '/, "")
+        .replace(/' does not exist on type 'typeof Deno'\./, "")
+        .replace(suggestionMessagePattern, "");
+      const suggestion = messageText.match(suggestionMessagePattern);
+      const replacedMessageText = messageText.replace(
+        suggestionMessagePattern,
+        ""
+      );
+      if (suggestion && unstableDenoGlobalProperties.includes(property)) {
+        const suggestedProperty = suggestion[1];
+        return `${replacedMessageText} 'Deno.${property}' is an unstable API. Did you forget to run with the '--unstable' flag, or did you mean '${suggestedProperty}'?`;
+      }
+      break;
     }
   }
+
   return messageText;
 }
 

cli/tests/integration_tests.rs

@@ -2073,6 +2073,12 @@ itest!(unstable_enabled_js {
   output: "unstable_enabled_js.out",
 });
 
+itest!(unstable_disabled_ts2551 {
+  args: "run --reload unstable_ts2551.ts",
+  exit_code: 1,
+  output: "unstable_disabled_ts2551.out",
+});
+
 itest!(_053_import_compression {
   args: "run --quiet --reload --allow-net 053_import_compression/main.ts",
   output: "053_import_compression.out",

cli/tests/unstable_disabled_ts2551.out

@@ -0,0 +1,10 @@
+[WILDCARD]
+error: TS2551 [ERROR]: Property 'ppid' does not exist on type 'typeof Deno'. 'Deno.ppid' is an unstable API. Did you forget to run with the '--unstable' flag, or did you mean 'pid'?
+console.log(Deno.ppid);
+                 ~~~~
+    at [WILDCARD]cli/tests/unstable_ts2551.ts:1:18
+
+    'pid' is declared here.
+      export const pid: number;
+                   ~~~
+        at asset:///lib.deno.ns.d.ts:[WILDCARD]

cli/tests/unstable_ts2551.ts

@@ -0,0 +1 @@
+console.log(Deno.ppid);