Avoid duplicate and stale report requests

assets/javascripts/discourse/components/hledger-dashboard.gjs

@@ -28,6 +28,10 @@ export default class HledgerDashboard extends Component {
   @tracked beginDate = null;
   @tracked endDate = null;
 
+  #inflight = null;
+  #lastKey = null;
+  #requestId = 0;
+
   constructor() {
     super(...arguments);
     this.loadReport();
@@ -103,6 +107,16 @@ export default class HledgerDashboard extends Component {
       return;
     }
 
+    const key = `${this.selectedReport}|${this.beginDate}|${this.endDate}`;
+
+    if (key === this.#lastKey && !this.error) {
+      return;
+    }
+
+    this.#lastKey = key;
+    const requestId = ++this.#requestId;
+
+    this.#inflight?.abort();
     this.loading = true;
     this.error = null;
 
@@ -115,16 +129,27 @@ export default class HledgerDashboard extends Component {
     }
 
     try {
-      this.report = await ajax(
+      const promise = ajax(
         `/hledger/topics/${topicId}/reports/${this.selectedReport}`,
         { data }
       );
+      this.#inflight = promise;
+      const report = await promise;
+
+      if (requestId === this.#requestId) {
+        this.report = report;
+      }
     } catch (e) {
-      this.report = null;
-      this.error =
-        e?.jqXHR?.responseJSON?.errors?.[0] || i18n("hledger.errors.generic");
+      if (requestId === this.#requestId) {
+        this.report = null;
+        this.error =
+          e?.jqXHR?.responseJSON?.errors?.[0] || i18n("hledger.errors.generic");
+      }
     } finally {
-      this.loading = false;
+      if (requestId === this.#requestId) {
+        this.loading = false;
+        this.#inflight = null;
+      }
     }
   }
 

test/javascripts/acceptance/hledger-test.js

@@ -260,6 +260,8 @@ const transactionsReport = {
 acceptance("Hledger plugin", function (needs) {
   needs.settings({ hledger_enabled: true });
 
+  const requestCounts = { accounts: 0, equity: 0 };
+
   needs.pretender((server, helper) => {
     server.get("/t/45.json", () => {
       const topic = cloneJSON(topicFixtures["/t/28830/1.json"]);
@@ -267,12 +269,14 @@ acceptance("Hledger plugin", function (needs) {
       return helper.response(topic);
     });
 
-    server.get(`/hledger/topics/${TOPIC_ID}/reports/accounts`, () =>
-      helper.response(accountsReport)
-    );
-    server.get(`/hledger/topics/${TOPIC_ID}/reports/equity`, () =>
-      helper.response(equityReport)
-    );
+    server.get(`/hledger/topics/${TOPIC_ID}/reports/accounts`, () => {
+      requestCounts.accounts++;
+      return helper.response(accountsReport);
+    });
+    server.get(`/hledger/topics/${TOPIC_ID}/reports/equity`, () => {
+      requestCounts.equity++;
+      return helper.response(equityReport);
+    });
     server.get(`/hledger/topics/${TOPIC_ID}/reports/balance_sheet`, () =>
       helper.response(balanceSheetReport)
     );
@@ -452,6 +456,24 @@ acceptance("Hledger plugin", function (needs) {
       .hasText("Server");
   });
 
+  test("does not issue duplicate requests for the same report", async function (assert) {
+    requestCounts.accounts = 0;
+    requestCounts.equity = 0;
+
+    await visit("/t/-/45");
+
+    assert.strictEqual(requestCounts.accounts, 1, "loads accounts once");
+
+    await click(".hledger-dashboard__toolbar .btn:nth-of-type(4)");
+    assert.strictEqual(requestCounts.equity, 1, "loads equity once");
+
+    await click(".hledger-dashboard__toolbar .btn:nth-of-type(4)");
+    assert.strictEqual(requestCounts.equity, 1, "ignores the current report");
+
+    await click(".hledger-dashboard__toolbar .btn:nth-of-type(1)");
+    assert.strictEqual(requestCounts.accounts, 2, "reloads on report change");
+  });
+
   test("shows the transaction log", async function (assert) {
     await visit("/t/-/45");