From 4fbda6cd9f9520f0fc0e49353f8da46280eb6f55 Mon Sep 17 00:00:00 2001
From: mstuartf <mstuartflood@gmail.com>
Date: Fri, 1 Jul 2022 17:56:26 +0100
Subject: [PATCH] fix(PPDSC-2164): assistive text (#249)

* fix(PPDSC-2164): add tests for bug expected outcome

* fix(PPDSC-2164): do not set aria-describedby if no assistive text

- Update assistiveTextId context value inside AssistiveText component so that it is only set if this component exists within the parent.

* fix(PPDSC-2164): update failing fieldset snapshots
---
 .../__snapshots__/fieldset.test.tsx.snap      |  6 --
 src/form/__tests__/form.test.tsx              | 60 +++++++++++++++++++
 src/form/context.ts                           |  1 +
 src/form/form-input.tsx                       | 24 ++++++--
 4 files changed, 80 insertions(+), 11 deletions(-)

diff --git a/src/fieldset/__tests__/__snapshots__/fieldset.test.tsx.snap b/src/fieldset/__tests__/__snapshots__/fieldset.test.tsx.snap
index 5a8d46ece0..d9eb2a02a3 100644
--- a/src/fieldset/__tests__/__snapshots__/fieldset.test.tsx.snap
+++ b/src/fieldset/__tests__/__snapshots__/fieldset.test.tsx.snap
@@ -647,7 +647,6 @@ exports[`Fieldset renders fieldset with large form inputs 1`] = `
       class="emotion-2"
     >
       <input
-        aria-describedby="mock-nk-1-assistive-text"
         aria-invalid="false"
         class="emotion-3"
         id="mock-nk-1"
@@ -670,7 +669,6 @@ exports[`Fieldset renders fieldset with large form inputs 1`] = `
           class="emotion-7"
         >
           <input
-            aria-describedby="mock-nk-1-assistive-text"
             class="emotion-8"
             data-testid="checkbox-input"
             id="mock-nk-1"
@@ -1337,7 +1335,6 @@ exports[`Fieldset renders fieldset with medium form inputs 1`] = `
       class="emotion-2"
     >
       <input
-        aria-describedby="mock-nk-1-assistive-text"
         aria-invalid="false"
         class="emotion-3"
         id="mock-nk-1"
@@ -1360,7 +1357,6 @@ exports[`Fieldset renders fieldset with medium form inputs 1`] = `
           class="emotion-7"
         >
           <input
-            aria-describedby="mock-nk-1-assistive-text"
             class="emotion-8"
             data-testid="checkbox-input"
             id="mock-nk-1"
@@ -2027,7 +2023,6 @@ exports[`Fieldset renders fieldset with small form inputs 1`] = `
       class="emotion-2"
     >
       <input
-        aria-describedby="mock-nk-1-assistive-text"
         aria-invalid="false"
         class="emotion-3"
         id="mock-nk-1"
@@ -2050,7 +2045,6 @@ exports[`Fieldset renders fieldset with small form inputs 1`] = `
           class="emotion-7"
         >
           <input
-            aria-describedby="mock-nk-1-assistive-text"
             class="emotion-8"
             data-testid="checkbox-input"
             id="mock-nk-1"
diff --git a/src/form/__tests__/form.test.tsx b/src/form/__tests__/form.test.tsx
index d9e5adad7d..0e9ce27c73 100644
--- a/src/form/__tests__/form.test.tsx
+++ b/src/form/__tests__/form.test.tsx
@@ -708,4 +708,64 @@ describe('FormInput', () => {
     });
     expect(await findByTestId('error-icon')).not.toBeNull();
   });
+
+  describe('input.aria-describedby', () => {
+    const INPUT_ID = 'test-input-1';
+    let assistiveTextId;
+
+    test('is set to assistive text id in default state', () => {
+      const {getByText, getByTestId} = renderWithImplementation(Form, {
+        onSubmit: () => {},
+        children: (
+          <FormInput id={INPUT_ID} name="test-input">
+            <FormInputLabel>Test input</FormInputLabel>
+            <FormInputTextField data-testid="text-field-test-input" />
+            <FormInputAssistiveText>Assistive Text</FormInputAssistiveText>
+          </FormInput>
+        ),
+      });
+
+      assistiveTextId = `${INPUT_ID}-assistive-text`;
+
+      const assistiveText = getByText('Assistive Text');
+      expect(assistiveText).toHaveAttribute('id', assistiveTextId);
+      const input = getByTestId('text-field-test-input');
+      expect(input).toHaveAttribute('aria-describedby', assistiveTextId);
+    });
+
+    test('is not set if no assistive text is provided', () => {
+      const {getByTestId} = renderWithImplementation(Form, {
+        onSubmit: () => {},
+        children: (
+          <FormInput id={INPUT_ID} name="test-input">
+            <FormInputLabel>Test input</FormInputLabel>
+            <FormInputTextField data-testid="text-field-test-input" />
+          </FormInput>
+        ),
+      });
+
+      const input = getByTestId('text-field-test-input');
+      expect(input).not.toHaveAttribute('aria-describedby');
+    });
+
+    test('is set to assistive text id in invalid state', () => {
+      const {getByText, getByTestId} = renderWithImplementation(Form, {
+        onSubmit: () => {},
+        children: (
+          <FormInput id={INPUT_ID} state="invalid" name="test-input">
+            <FormInputLabel>Test input</FormInputLabel>
+            <FormInputTextField data-testid="text-field-test-input" />
+            <FormInputAssistiveText>Assistive Text</FormInputAssistiveText>
+          </FormInput>
+        ),
+      });
+
+      assistiveTextId = `${INPUT_ID}-error-text`;
+
+      const assistiveText = getByText('Assistive Text');
+      expect(assistiveText).toHaveAttribute('id', assistiveTextId);
+      const input = getByTestId('text-field-test-input');
+      expect(input).toHaveAttribute('aria-describedby', assistiveTextId);
+    });
+  });
 });
diff --git a/src/form/context.ts b/src/form/context.ts
index 59f1bae46f..7db8995ace 100644
--- a/src/form/context.ts
+++ b/src/form/context.ts
@@ -29,6 +29,7 @@ export const FormInputContext = createContext<{
   id?: string;
   labelId?: string;
   assistiveTextId?: string;
+  setAssistiveTextId?: (id: string) => void;
   statusIcon?: React.ReactNode;
   isRequired?: boolean;
 }>({});
diff --git a/src/form/form-input.tsx b/src/form/form-input.tsx
index 60c327cee7..0b8251f1ec 100644
--- a/src/form/form-input.tsx
+++ b/src/form/form-input.tsx
@@ -1,4 +1,4 @@
-import React, {useContext} from 'react';
+import React, {useContext, useEffect, useState} from 'react';
 import composeRefs from '@seznam/compose-react-refs';
 import {Label, LabelProps} from '../label';
 import {TextField} from '../text-field/text-field';
@@ -45,6 +45,7 @@ const ThemelessFormInput = ({
   const [autoGeneratedId] = useReactKeys(1);
 
   const currentID = id || autoGeneratedId;
+  const [assistiveTextId, setAssistiveTextId] = useState<string | undefined>();
 
   const theme = useTheme();
 
@@ -61,9 +62,6 @@ const ThemelessFormInput = ({
     <FormEntry name={name} rules={rules}>
       {({ref, state: stateContext, onChange, onBlur, error}) => {
         const state = stateProp || stateContext;
-        const assistiveTextId =
-          (state === 'invalid' && `${currentID}-error-text`) ||
-          `${currentID}-assistive-text`;
         const labelId = `${currentID}-label`;
 
         const statusIcon = getStatusIcon({state, iconSize: validationIconSize});
@@ -80,6 +78,7 @@ const ThemelessFormInput = ({
           ref,
           id: currentID,
           assistiveTextId,
+          setAssistiveTextId,
           labelId,
           statusIcon,
           isRequired,
@@ -202,7 +201,22 @@ export const FormInputAssistiveText = ({
   overrides,
   ...props
 }: AssistiveTextProps & {validationIcon?: boolean}) => {
-  const {size, state, error, assistiveTextId} = useFormFieldContext();
+  const {
+    size,
+    state,
+    error,
+    assistiveTextId,
+    setAssistiveTextId,
+    id,
+  } = useFormFieldContext();
+
+  useEffect(() => {
+    if (setAssistiveTextId) {
+      setAssistiveTextId(
+        state === 'invalid' ? `${id}-error-text` : `${id}-assistive-text`,
+      );
+    }
+  }, [state, id, setAssistiveTextId]);
 
   const theme = useTheme();