Tweak the consumer + Crosis both sides aborted check to allow Crosis to unilaterally abort. (#193)

* Eliminate the aborted check on both sides.

* Restore the option to return aborted; add invariant check.

* Types.

* Clearer docs.

* clarify type comment on Aborted

* linty

* v13.1.0. (#194)

Author: gburtini

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@replit/crosis",
-  "version": "13.0.0",
+  "version": "13.1.0",
   "description": "Goval connection and channel manager",
   "files": [
     "/dist"

src/client.ts

@@ -1103,36 +1103,24 @@ export class Client<Ctx = null> {
       this.fetchTokenAbortController = null;
 
       const connectionMetadata = connectionMetadataFetchResult;
-      const aborted = connectionMetadata.error === FetchConnectionMetadataError.Aborted;
-
-      if (abortController.signal.aborted !== aborted) {
-        // the aborted return value and the abort signal should be equivalent
-        if (abortController.signal.aborted) {
-          // In cases where our abort signal has been called means `client.close` was called
-          // that means we shouldn't be calling `handleConnectError` because chan0Cb is null!
-          this.onUnrecoverableError(
-            new CrosisError(
-              'Expected abort returned from fetchConnectionMetadata to be truthy when the controller aborts',
-            ),
-          );
-
-          return;
-        }
 
-        // the user shouldn't return abort without the abort signal being called, if aborting is desired
-        // client.close should be called
-        this.onUnrecoverableError(
-          new CrosisError(
-            'Abort should only be truthy returned when the abort signal is triggered',
-          ),
-        );
+      if (abortController.signal.aborted) {
+        // Just return. The user called `client.close` leading to a connectionMetadata abort
+        // chan0Cb will be called with with an error Channel close, no need to do anything here.
 
         return;
       }
 
       if (connectionMetadata.error === FetchConnectionMetadataError.Aborted) {
-        // Just return. The user called `client.close` leading to a connectionMetadata abort
-        // chan0Cb will be called with with an error Channel close, no need to do anything here.
+        // A client cannot unilaterally choose to abort. If the abortController is not aborted
+        // the client must either return an error or valid metadata.
+
+        this.onUnrecoverableError(
+          new CrosisError(
+            'Client received abort from fetchConnectionMetadata, but the request was not aborted.',
+          ),
+        );
+
         return;
       }
 

src/types.ts

@@ -10,7 +10,8 @@ export enum ConnectionState {
 
 export enum FetchConnectionMetadataError {
   /**
-   * Fetch was aborted.
+   * Fetch was aborted. A client may return this only if
+   * the `AbortSignal` was already aborted.
    */
   Aborted = 'Aborted',