fix: don't render spinner in non-TTY terminal

packages/amplify-prompts/src/__tests__/spinner.test.ts

@@ -0,0 +1,66 @@
+import { AmplifySpinner } from '../progressbars/spinner';
+import { AmplifyTerminal } from '../progressbars/terminal';
+
+jest.mock('../progressbars/terminal');
+const amplifyTerminalMocked = jest.mocked(AmplifyTerminal);
+
+beforeEach(() => {
+  jest.resetAllMocks();
+});
+
+describe('in non-TTY terminal', () => {
+  beforeEach(() => {
+    jest.spyOn(AmplifyTerminal.prototype, 'isTTY').mockReturnValue(false);
+  });
+
+  it('is noop', () => {
+    const spinner = new AmplifySpinner();
+
+    spinner.start('initial message');
+    spinner.resetMessage('other message');
+    spinner.stop('last message');
+
+    expect(amplifyTerminalMocked.mock.instances.length).toEqual(1);
+    expect(AmplifyTerminal).toHaveBeenCalledTimes(1);
+    expect(amplifyTerminalMocked.mock.instances[0].writeLines).toHaveBeenCalledTimes(0);
+    expect(amplifyTerminalMocked.mock.instances[0].cursor).toHaveBeenCalledTimes(0);
+    expect(amplifyTerminalMocked.mock.instances[0].getLastHeight).toHaveBeenCalledTimes(0);
+    expect(amplifyTerminalMocked.mock.instances[0].newLine).toHaveBeenCalledTimes(0);
+  });
+});
+
+describe('in TTY terminal', () => {
+  let spinner: AmplifySpinner;
+  beforeEach(() => {
+    jest.spyOn(AmplifyTerminal.prototype, 'isTTY').mockReturnValue(true);
+    spinner = new AmplifySpinner();
+  });
+
+  afterEach(() => {
+    // always stop the spinner to clear internal timer.
+    spinner.stop();
+  });
+
+  it('starts spinner renders initial message, and stops spinner', async () => {
+    const initialMessage = 'initial message';
+    const intermediateMessage = 'intermediate message';
+    const lastMessage = 'last message';
+    spinner.start(initialMessage);
+    spinner.resetMessage(intermediateMessage);
+    // wait for default rate of 50ms plus small delta to let spinner render new message.
+    await new Promise((resolve) => setTimeout(resolve, 50 + 10));
+    spinner.stop(lastMessage);
+    expect(amplifyTerminalMocked.mock.instances.length).toEqual(1);
+    expect(AmplifyTerminal).toHaveBeenCalledTimes(1);
+    expect(amplifyTerminalMocked.mock.instances[0].writeLines).toHaveBeenCalledTimes(3);
+    expect(amplifyTerminalMocked.mock.instances[0].writeLines).toHaveBeenCalledWith([{ color: '', renderString: `⠋ ${initialMessage}` }]);
+    expect(amplifyTerminalMocked.mock.instances[0].writeLines).toHaveBeenCalledWith([
+      { color: '', renderString: `⠙ ${intermediateMessage}` },
+    ]);
+    expect(amplifyTerminalMocked.mock.instances[0].writeLines).toHaveBeenCalledWith([{ color: 'green', renderString: lastMessage }]);
+    expect(amplifyTerminalMocked.mock.instances[0].cursor).toHaveBeenCalledTimes(2);
+    expect(amplifyTerminalMocked.mock.instances[0].cursor).toHaveBeenCalledWith(false);
+    expect(amplifyTerminalMocked.mock.instances[0].getLastHeight).toHaveBeenCalledTimes(0);
+    expect(amplifyTerminalMocked.mock.instances[0].newLine).toHaveBeenCalledTimes(0);
+  });
+});

packages/amplify-prompts/src/progressbars/spinner.ts

@@ -28,7 +28,7 @@ export class AmplifySpinner {
    * Render function
    */
   private render(): void {
-    if (!this.terminal) {
+    if (!this.terminal || !this.terminal.isTTY()) {
       return;
     }
     if (this.timer) {
@@ -52,6 +52,9 @@ export class AmplifySpinner {
     if (!this.terminal) {
       this.terminal = new AmplifyTerminal();
     }
+    if (!this.terminal.isTTY()) {
+      return;
+    }
     this.prefixText = text ? text.replace('\n', '') : this.prefixText;
     this.terminal.cursor(false);
     this.render();
@@ -61,7 +64,7 @@ export class AmplifySpinner {
    * Reset spinner message
    */
   resetMessage(text: string | null): void {
-    if (!this.terminal) {
+    if (!this.terminal || !this.terminal.isTTY()) {
       this.start(text);
       return;
     }
@@ -75,16 +78,18 @@ export class AmplifySpinner {
     if (!this.terminal) {
       return;
     }
-    const lines: TerminalLine[] = [
-      {
-        renderString: text || '',
-        color: success ? 'green' : 'red',
-      },
-    ];
+    if (this.terminal.isTTY()) {
+      const lines: TerminalLine[] = [
+        {
+          renderString: text || '',
+          color: success ? 'green' : 'red',
+        },
+      ];
 
-    clearTimeout(this.timer);
-    this.terminal.writeLines(lines);
-    this.terminal.cursor(true);
+      clearTimeout(this.timer);
+      this.terminal.writeLines(lines);
+      this.terminal.cursor(true);
+    }
     this.terminal = null;
   }
 }