poc query de-duplication

Author: shakyShane

special-pages/pages/history/app/history.service.js

@@ -29,6 +29,9 @@ export class HistoryService {
                 });
             },
         }).withUpdater((old, next, trigger) => {
+            /**
+             * Manual updates, always accept the update
+             */
             if (trigger === 'manual') {
                 return next;
             }

special-pages/pages/new-tab/app/service.js

@@ -201,7 +201,7 @@ export class Service {
 }
 
 class NonOverlapping {
-    /** @type {null|{promise: any}} */
+    /** @type {null|{promise: any, id: string}} */
     _ongoing = null;
 
     /**
@@ -219,12 +219,19 @@ class NonOverlapping {
         if (this._ongoing?.promise) {
             this._ongoing.promise.cancelled = true;
         }
+        // todo: where to put this de-duplication of queries?
+        const id = JSON.stringify(params);
+        if (this._ongoing?.id === id) {
+            return;
+        }
+
         // eslint-disable-next-line promise/prefer-await-to-then
         const promise = this.service.impl.initial(params).then((data) => {
             if (/** @type {any} */ (promise).cancelled) return;
             this.service.accept(data, 'trigger-fetch');
             this._ongoing = null;
         });
-        this._ongoing = { promise };
+
+        this._ongoing = { promise, id };
     }
 }