From 763775a0f5a1e77430638abcd7b56c7a3e106d49 Mon Sep 17 00:00:00 2001
From: Jez Barnsley <jbarnsley.github@gmail.com>
Date: Tue, 2 Dec 2025 11:25:50 +0000
Subject: [PATCH] Handles a component that doesn't exist in plugin yet

---
 .../engine/components/helpers/components.ts   | 10 +++++--
 .../engine/components/helpers/helpers.test.ts | 28 +++++++++++--------
 2 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/src/server/plugins/engine/components/helpers/components.ts b/src/server/plugins/engine/components/helpers/components.ts
index d307e6517..4c852b634 100644
--- a/src/server/plugins/engine/components/helpers/components.ts
+++ b/src/server/plugins/engine/components/helpers/components.ts
@@ -1,6 +1,7 @@
 import { ComponentType, type ComponentDef } from '@defra/forms-model'
 
 import { config } from '~/src/config/index.js'
+import { createLogger } from '~/src/server/common/helpers/logging/logger.js'
 import { type ComponentBase } from '~/src/server/plugins/engine/components/ComponentBase.js'
 import { ListFormComponent } from '~/src/server/plugins/engine/components/ListFormComponent.js'
 import { escapeMarkdown } from '~/src/server/plugins/engine/components/helpers/index.js'
@@ -8,6 +9,8 @@ import * as Components from '~/src/server/plugins/engine/components/index.js'
 import { markdown } from '~/src/server/plugins/engine/components/markdownParser.js'
 import { type FormState } from '~/src/server/plugins/engine/types.js'
 
+const logger = createLogger()
+
 // All component instances
 export type Component = InstanceType<
   (typeof Components)[keyof typeof Components]
@@ -191,10 +194,11 @@ export function createComponent(
     case ComponentType.HiddenField:
       component = new Components.HiddenField(def, options)
       break
-  }
 
-  if (typeof component === 'undefined') {
-    throw new Error(`Component type ${def.type} does not exist`)
+    default:
+      // @ts-expect-error - may be a type that isn't in ComponentType
+      logger.error(`Component type ${def.type} does not exist`)
+      component = new Components.TextField(def, options)
   }
 
   return component
diff --git a/src/server/plugins/engine/components/helpers/helpers.test.ts b/src/server/plugins/engine/components/helpers/helpers.test.ts
index e597fa0d1..37012047d 100644
--- a/src/server/plugins/engine/components/helpers/helpers.test.ts
+++ b/src/server/plugins/engine/components/helpers/helpers.test.ts
@@ -6,6 +6,7 @@ import { HiddenField } from '~/src/server/plugins/engine/components/HiddenField.
 import { LatLongField } from '~/src/server/plugins/engine/components/LatLongField.js'
 import { NationalGridFieldNumberField } from '~/src/server/plugins/engine/components/NationalGridFieldNumberField.js'
 import { OsGridRefField } from '~/src/server/plugins/engine/components/OsGridRefField.js'
+import { TextField } from '~/src/server/plugins/engine/components/TextField.js'
 import { createComponent } from '~/src/server/plugins/engine/components/helpers/components.js'
 import {
   createLowerFirstExpression,
@@ -19,17 +20,22 @@ const formModel = new FormModel(definition, {
 })
 
 describe('helpers tests', () => {
-  test('should throw if invalid type', () => {
-    expect(() =>
-      createComponent(
-        {
-          type: 'invalid-type'
-        } as unknown as ComponentDef,
-        {
-          model: formModel
-        }
-      )
-    ).toThrow('Component type invalid-type does not exist')
+  test('should default if invalid type', () => {
+    const component = createComponent(
+      {
+        type: 'invalid-type',
+        name: 'InvalidField',
+        shortDescription: 'Short desc',
+        title: 'My invalid field',
+        options: {}
+      } as unknown as ComponentDef,
+      {
+        model: formModel
+      }
+    )
+    expect(component).toBeInstanceOf(TextField)
+    expect(component.name).toBe('InvalidField')
+    expect(component.title).toBe('My invalid field')
   })
 
   test('should create EastingNorthingField component', () => {