From 86a4a0f72ddd2378dc55433ac83ae650f5c3e22d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Minh=20Tr=C3=AD?= <tritri251214@gmail.com>
Date: Tue, 17 May 2022 14:52:00 +0700
Subject: [PATCH] [Scaffolder] Get data of other fields in Form from a custom
 field
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Allows to use e.g.
```
const CustomFieldExtensionComponent(props: FieldExtensionComponentProps<string[]>) => {
     const { formContext } = props;
     ....
};

const CustomFieldExtension = scaffolderPlugin.provide(
  createScaffolderFieldExtension({
    name: ...,
    component: CustomFieldExtensionComponent,
    validation: ....
  })
);
```

Signed-off-by: Minh Trí <tritri251214@gmail.com>
---
 .changeset/scaffolder-form-context.md         | 21 +++++++++++++++++++
 .../writing-custom-field-extensions.md        | 17 +++++++++++++++
 .../MultistepJsonForm/MultistepJsonForm.tsx   |  1 +
 3 files changed, 39 insertions(+)
 create mode 100644 .changeset/scaffolder-form-context.md

diff --git a/.changeset/scaffolder-form-context.md b/.changeset/scaffolder-form-context.md
new file mode 100644
index 0000000000..08295c6b85
--- /dev/null
+++ b/.changeset/scaffolder-form-context.md
@@ -0,0 +1,21 @@
+---
+'@backstage/plugin-scaffolder': minor
+---
+
+Get data of other fields in Form from a custom field in template Scaffolder.
+following:
+
+```tsx
+const CustomFieldExtensionComponent(props: FieldExtensionComponentProps<string[]>) => {
+  const { formContext } = props;
+  ...
+};
+
+const CustomFieldExtension = scaffolderPlugin.provide(
+  createScaffolderFieldExtension({
+    name: ...,
+    component: CustomFieldExtensionComponent,
+    validation: ...
+  })
+);
+```
diff --git a/docs/features/software-templates/writing-custom-field-extensions.md b/docs/features/software-templates/writing-custom-field-extensions.md
index 8618e04781..5fe3349285 100644
--- a/docs/features/software-templates/writing-custom-field-extensions.md
+++ b/docs/features/software-templates/writing-custom-field-extensions.md
@@ -161,3 +161,20 @@ spec:
           description: My custom name for the component
           ui:field: MyCustomExtension
 ```
+
+## Get data of other fields in Form from a Custom Field Extension
+
+```tsx
+const CustomFieldExtensionComponent(props: FieldExtensionComponentProps<string[]>) => {
+  const { formContext } = props;
+  ...
+};
+
+const CustomFieldExtension = scaffolderPlugin.provide(
+  createScaffolderFieldExtension({
+    name: ...,
+    component: CustomFieldExtensionComponent,
+    validation: ...
+  })
+);
+```
diff --git a/plugins/scaffolder/src/components/MultistepJsonForm/MultistepJsonForm.tsx b/plugins/scaffolder/src/components/MultistepJsonForm/MultistepJsonForm.tsx
index a868c50d7a..8db409ed38 100644
--- a/plugins/scaffolder/src/components/MultistepJsonForm/MultistepJsonForm.tsx
+++ b/plugins/scaffolder/src/components/MultistepJsonForm/MultistepJsonForm.tsx
@@ -198,6 +198,7 @@ export const MultistepJsonForm = (props: Props) => {
                   widgets={widgets}
                   noHtml5Validate
                   formData={formData}
+                  formContext={formData}
                   onChange={onChange}
                   onSubmit={e => {
                     if (e.errors.length === 0) handleNext();