Added error callback for when we fail in onEnd

packages/demo/demos/transformerException.mjs

@@ -0,0 +1,25 @@
+import { prompt } from '@inquirer';
+
+const demo = async () => {
+  try {
+    await prompt([
+      {
+        type: 'input',
+        message: 'Foo quotient',
+        name: 'foo',
+        transformer: (x) => {
+          if (x === 1) {
+            throw new Error('failing because of the reason');
+          }
+          return x;
+        },
+        default: 1,
+      },
+    ]);
+
+    console.log('Done');
+  } catch (e) {
+    console.error('An _expected_ error', e);
+  }
+};
+export default demo;

packages/demo/index.mjs

@@ -10,6 +10,7 @@ import inputDemo from './demos/input.mjs';
 import passwordDemo from './demos/password.mjs';
 import rawlistDemo from './demos/rawlist.mjs';
 import selectDemo from './demos/select.mjs';
+import transformerExceptionDemo from './demos/transformerException.mjs';
 
 const demos = {
   checkbox: checkboxDemo,
@@ -20,6 +21,7 @@ const demos = {
   password: passwordDemo,
   rawlist: rawlistDemo,
   select: selectDemo,
+  transformerExceptionDemo,
 };
 
 function askNextDemo() {

packages/inquirer/examples/transformer-exception.js

@@ -0,0 +1,23 @@
+import inquirer from '../lib/inquirer.js';
+(async () => {
+  try {
+    await inquirer.prompt([
+      {
+        type: 'input',
+        message: 'Foo quotient',
+        name: 'foo',
+        transformer(x) {
+          if (x === 1) {
+            throw new Error('failing because of the reason');
+          }
+          return x;
+        },
+        default: 1,
+      },
+    ]);
+
+    console.log('Done');
+  } catch (e) {
+    console.error('An _expected_ error', e);
+  }
+})();

packages/inquirer/lib/prompts/confirm.js

@@ -36,8 +36,9 @@ export default class ConfirmPrompt extends Base {
    * @return {this}
    */
 
-  _run(cb) {
+  _run(cb, errorCb) {
     this.done = cb;
+    this.error = errorCb;
 
     // Once user confirm (enter key)
     const events = observe(this.rl);
@@ -79,14 +80,18 @@ export default class ConfirmPrompt extends Base {
   onEnd(input) {
     this.status = 'answered';
 
-    let output = this.opt.filter(input);
-    if (this.opt.transformer) {
-      output = this.opt.transformer(output);
+    try {
+      let output = this.opt.filter(input);
+      if (this.opt.transformer) {
+        output = this.opt.transformer(output);
+      }
+      this.render(output);
+
+      this.screen.done();
+      this.done(output);
+    } catch (error) {
+      this.error(error);
     }
-    this.render(output);
-
-    this.screen.done();
-    this.done(output);
   }
 
   /**

packages/inquirer/lib/prompts/input.js

@@ -14,8 +14,9 @@ export default class InputPrompt extends Base {
    * @return {this}
    */
 
-  _run(cb) {
+  _run(cb, errorCb) {
     this.done = cb;
+    this.error = errorCb;
 
     // Once user confirm (enter key)
     const events = observe(this.rl);
@@ -82,11 +83,15 @@ export default class InputPrompt extends Base {
     this.answer = state.value;
     this.status = 'answered';
 
-    // Re-render prompt
-    this.render();
+    try {
+      // Re-render prompt
+      this.render();
 
-    this.screen.done();
-    this.done(state.value);
+      this.screen.done();
+      this.done(state.value);
+    } catch (error) {
+      this.error(error);
+    }
   }
 
   onError({ value = '', isValid }) {

packages/inquirer/test/specs/inquirer.test.js

@@ -778,6 +778,68 @@ describe('inquirer.prompt', () => {
         expect(answers.prefiled.nested).toEqual('newValue');
       });
     });
+
+    it('should not mask the original error thrown in the onEnd function for transformer (input)', async () => {
+      const expectedError = 'Foo';
+      const prompts = [
+        {
+          type: 'input',
+          name: 'q1',
+          message: 'message',
+          transformer(x) {
+            if (x === 1) {
+              throw new Error(expectedError);
+            }
+            return x;
+          },
+          default: 1,
+        },
+      ];
+
+      const promise = prompt(prompts);
+
+      promise.ui.rl.emit('line');
+
+      return promise
+        .then(() => {
+          // Failure
+          expect(true).toEqual(false);
+        })
+        .catch((error) => {
+          expect(error.message).toEqual(expectedError);
+        });
+    });
+
+    it('should not mask the original error thrown in the onEnd function for transformer (confirm)', async () => {
+      const expectedError = 'Foo';
+      const prompts = [
+        {
+          type: 'confirm',
+          name: 'q1',
+          message: 'message',
+          transformer(x) {
+            if (x === false) {
+              throw new Error(expectedError);
+            }
+            return x;
+          },
+          default: false,
+        },
+      ];
+
+      const promise = prompt(prompts);
+
+      promise.ui.rl.emit('line');
+
+      return promise
+        .then(() => {
+          // Failure
+          expect(true).toEqual(false);
+        })
+        .catch((error) => {
+          expect(error.message).toEqual(expectedError);
+        });
+    });
   });
 
   describe('#registerPrompt()', () => {