TypeScript: remove getState() and public ConnectionState

.NET removed `CopilotClient.State` and `ConnectionState` in commit
b00fd8c (Phase 4d/4e). Python matched this in PR #1376. TypeScript was
the last SDK still exposing both — drop them for cross-SDK consistency.

- `CopilotClient.getState(): ConnectionState` removed.
- Public `ConnectionState` type alias removed from `types.ts` and the
  index re-exports.
- The private `state` field on `CopilotClient` stays (still used by
  start/stop to gate behavior); its type is now an inline union
  declaration instead of the exported alias.
- Unit test for unexpected child-process death now reads the private
  `state` field via `(client as any).state` since the behaviour being
  tested (state transition on async disconnect) is genuinely internal.
- E2E `client.getState() === "..."` assertions are dropped — they were
  pure tautologies once `start()` returned without throwing.
- `nodejs/README.md` no longer documents `getState()`.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: SteveSandersonMS

nodejs/README.md

@@ -131,10 +131,6 @@ Resume an existing session. Returns the session with `workspacePath` populated i
 
 Ping the server to check connectivity.
 
-##### `getState(): ConnectionState`
-
-Get current connection state.
-
 ##### `listSessions(filter?: SessionListFilter): Promise<SessionMetadata[]>`
 
 List all available sessions. Optionally filter by working directory context.

nodejs/src/client.ts

@@ -38,7 +38,6 @@ import { getTraceContext } from "./telemetry.js";
 import type {
     AutoModeSwitchRequest,
     AutoModeSwitchResponse,
-    ConnectionState,
     CopilotClientOptions,
     CustomAgentConfig,
     ExitPlanModeRequest,
@@ -251,7 +250,7 @@ export class CopilotClient {
     private socket: Socket | null = null;
     private runtimePort: number | null = null;
     private actualHost: string = "localhost";
-    private state: ConnectionState = "disconnected";
+    private state: "disconnected" | "connecting" | "connected" | "error" = "disconnected";
     private sessions: Map<string, CopilotSession> = new Map();
     private stderrBuffer: string = ""; // Captures CLI stderr for error messages
     /** Resolved connection mode chosen in the constructor. */
@@ -1039,22 +1038,6 @@ export class CopilotClient {
         return session;
     }
 
-    /**
-     * Gets the current connection state of the client.
-     *
-     * @returns The current connection state: "disconnected", "connecting", "connected", or "error"
-     *
-     * @example
-     * ```typescript
-     * if (client.getState() === "connected") {
-     *   const session = await client.createSession({ onPermissionRequest: approveAll });
-     * }
-     * ```
-     */
-    getState(): ConnectionState {
-        return this.state;
-    }
-
     /**
      * Sends a ping request to the server to verify connectivity.
      *

nodejs/src/index.ts

@@ -40,7 +40,6 @@ export type {
     AutoModeSwitchHandler,
     AutoModeSwitchRequest,
     AutoModeSwitchResponse,
-    ConnectionState,
     CopilotClientOptions,
     StdioRuntimeConnection,
     TcpRuntimeConnection,

nodejs/src/types.ts

@@ -1842,11 +1842,6 @@ export type TypedSessionEventHandler<T extends SessionEventType> = (
  */
 export type SessionEventHandler = (event: SessionEvent) => void;
 
-/**
- * Connection state
- */
-export type ConnectionState = "disconnected" | "connecting" | "connected" | "error";
-
 /**
  * Working directory context for a session
  */

nodejs/test/client.test.ts

@@ -984,15 +984,15 @@ describe("CopilotClient", () => {
             await client.start();
             onTestFinished(() => client.forceStop());
 
-            expect(client.getState()).toBe("connected");
+            expect((client as any).state).toBe("connected");
 
             // Kill the child process to simulate unexpected termination
             const proc = (client as any).cliProcess as import("node:child_process").ChildProcess;
             proc.kill();
 
             // Wait for the connection.onClose handler to fire
             await vi.waitFor(() => {
-                expect(client.getState()).toBe("disconnected");
+                expect((client as any).state).toBe("disconnected");
             });
         });
     });

nodejs/test/e2e/client.e2e.test.ts

@@ -56,29 +56,25 @@ describe("Client", () => {
         onTestFinishedForceStop(client);
 
         await client.start();
-        expect(client.getState()).toBe("connected");
 
         const pong = await client.ping("test message");
         expect(pong.message).toBe("pong: test message");
         expect(Date.parse(pong.timestamp)).not.toBeNaN();
 
         expect(await client.stop()).toHaveLength(0); // No errors on stop
-        expect(client.getState()).toBe("disconnected");
     });
 
     it("should start and connect to server using tcp", async () => {
         const client = new CopilotClient({ connection: RuntimeConnection.forTcp() });
         onTestFinishedForceStop(client);
 
         await client.start();
-        expect(client.getState()).toBe("connected");
 
         const pong = await client.ping("test message");
         expect(pong.message).toBe("pong: test message");
         expect(Date.parse(pong.timestamp)).not.toBeNaN();
 
         expect(await client.stop()).toHaveLength(0); // No errors on stop
-        expect(client.getState()).toBe("disconnected");
     });
 
     it.skipIf(process.platform === "darwin")(
@@ -101,7 +97,6 @@ describe("Client", () => {
             await new Promise((resolve) => setTimeout(resolve, 100));
 
             const errors = await client.stop();
-            expect(client.getState()).toBe("disconnected");
             if (errors.length > 0) {
                 expect(errors[0].message).toContain("Failed to disconnect session");
             }
@@ -117,7 +112,6 @@ describe("Client", () => {
 
         await client.createSession({ onPermissionRequest: approveAll });
         await client.forceStop();
-        expect(client.getState()).toBe("disconnected");
     });
 
     it("should get status with version and protocol info", async () => {

nodejs/test/e2e/client_options.e2e.test.ts

@@ -154,10 +154,8 @@ describe("Client options", async () => {
             }
         });
 
-        expect(client.getState()).toBe("disconnected");
 
         const session = await client.createSession({ onPermissionRequest: approveAll });
-        expect(client.getState()).toBe("connected");
         expect(session.sessionId).toMatch(/^[a-f0-9-]+$/);
 
         await session.disconnect();
@@ -183,7 +181,6 @@ describe("Client options", async () => {
 
         await client.start();
 
-        expect(client.getState()).toBe("connected");
         expect((client as unknown as { runtimePort: number }).runtimePort).toBe(port);
 
         const response = await client.ping("fixed-port");