fix: smooth terminal streaming

2026-04-21 20:47:17 +07:00
parent 39db3ea5ff
commit 6a03873d81
9 changed files with 1126 additions and 19 deletions
@@ -0,0 +1,79 @@
+import { describe, expect, test } from "vitest";
+import { TerminalOutputCoalescer } from "./terminal-output-coalescer.js";
+
+function createHarness() {
+  let nextTimer = 1;
+  const scheduled = new Map<number, { callback: () => void; delayMs: number }>();
+  const flushes: Array<{ payload: string; chars: number; bytes: number }> = [];
+  const coalescer = new TerminalOutputCoalescer({
+    timers: {
+      setTimeout: ((callback: () => void, delayMs?: number) => {
+        const id = nextTimer;
+        nextTimer += 1;
+        scheduled.set(id, { callback, delayMs: delayMs ?? 0 });
+        return id;
+      }) as typeof setTimeout,
+      clearTimeout: ((id: number) => {
+        scheduled.delete(id);
+      }) as typeof clearTimeout,
+    },
+    onFlush: ({ payload, chars, bytes }) => {
+      flushes.push({ payload: payload.toString("utf8"), chars, bytes });
+    },
+  });
+
+  return {
+    coalescer,
+    flushes,
+    scheduled,
+    runScheduled() {
+      const callbacks = Array.from(scheduled.values());
+      scheduled.clear();
+      for (const { callback } of callbacks) {
+        callback();
+      }
+    },
+  };
+}
+
+describe("TerminalOutputCoalescer", () => {
+  test("coalesces output into one 5ms flush window", () => {
+    const { coalescer, flushes, runScheduled, scheduled } = createHarness();
+
+    coalescer.handle("a");
+    coalescer.handle("b");
+    coalescer.handle("é");
+
+    expect(scheduled.size).toBe(1);
+    expect(Array.from(scheduled.values())).toEqual([
+      { callback: expect.any(Function), delayMs: 5 },
+    ]);
+    expect(flushes).toEqual([]);
+
+    runScheduled();
+
+    expect(flushes).toEqual([{ payload: "abé", chars: 3, bytes: 4 }]);
+  });
+
+  test("manual flush drains pending output and cancels the scheduled flush", () => {
+    const { coalescer, flushes, runScheduled, scheduled } = createHarness();
+
+    coalescer.handle("hello");
+    coalescer.flush();
+    runScheduled();
+
+    expect(scheduled.size).toBe(0);
+    expect(flushes).toEqual([{ payload: "hello", chars: 5, bytes: 5 }]);
+  });
+
+  test("dispose drops pending output", () => {
+    const { coalescer, flushes, runScheduled, scheduled } = createHarness();
+
+    coalescer.handle("pending");
+    coalescer.dispose();
+    runScheduled();
+
+    expect(scheduled.size).toBe(0);
+    expect(flushes).toEqual([]);
+  });
+});