Add the missing support of help texts to InputGroup (#663)

`InputGroup` now supports the `helpTexts` prop.

For `FileInputField`, `Select`, and `TextField`,
help text is not rendered within the `InputGroup`
context. The `helpTexts` prop of `InputGroup`
must be used instead.

Author: adamkudrna

src/components/Button/README.md

@@ -28,7 +28,7 @@ See [API](#api) for all available options.
 - **Don't overwhelm your UI** with too many high-emphasis actions. There should
     always be one but chances are that having more of them is not necessary.
 
-- Ensure the **button action is well recognazible** across your target audience.
+- Ensure the **button action is well recognizable** across your target audience.
     This is especially important when using the button [with an icon only](#icon-buttons).
 
 ## Priorities

src/components/FileInputField/FileInputField.jsx

@@ -223,15 +223,15 @@ export const FileInputField = React.forwardRef((props, ref) => {
             </Text>
           </button>
         </div>
-        {helpText && (
+        {(helpText && !inputGroupContext) && (
           <div
             className={styles.helpText}
             id={`${id}__helpText`}
           >
             {helpText}
           </div>
         )}
-        {validationText && (
+        {(validationText && !inputGroupContext) && (
           <div
             className={styles.validationText}
             id={`${id}__validationText`}
@@ -268,6 +268,9 @@ FileInputField.propTypes = {
   fullWidth: PropTypes.bool,
   /**
    * Optional help text.
+   *
+   * Help text is never rendered when the component is placed into `InputGroup`. Instead, the `InputGroup`
+   * component itself renders all help texts of its nested components.
    */
   helpText: PropTypes.node,
   /**
@@ -321,6 +324,9 @@ FileInputField.propTypes = {
   validationState: PropTypes.oneOf(['invalid', 'valid', 'warning']),
   /**
    * Validation message to be displayed.
+   *
+   * Validation text is never rendered when the component is placed into `InputGroup`. Instead, the `InputGroup`
+   * component itself renders all validation texts of its nested components.
    */
   validationText: PropTypes.node,
 };

src/components/InputGroup/InputGroup.jsx

@@ -18,6 +18,7 @@ import styles from './InputGroup.module.scss';
 export const InputGroup = ({
   children,
   disabled,
+  helpTexts,
   id,
   isLabelVisible,
   label,
@@ -89,6 +90,20 @@ export const InputGroup = ({
             {children}
           </InputGroupContext.Provider>
         </div>
+        {helpTexts && (
+          <ul
+            className={styles.helpText}
+            id={id && `${id}__helpTexts`}
+          >
+            {helpTexts.map((helpText) => (
+              <li key={helpText}>
+                <Text blockLevel>
+                  {helpText}
+                </Text>
+              </li>
+            ))}
+          </ul>
+        )}
         {validationTexts && (
           <ul
             className={styles.validationText}
@@ -111,6 +126,7 @@ export const InputGroup = ({
 InputGroup.defaultProps = {
   children: null,
   disabled: false,
+  helpTexts: null,
   id: undefined,
   isLabelVisible: true,
   layout: 'vertical',
@@ -133,6 +149,10 @@ InputGroup.propTypes = {
    * If `true`, the whole input group with all nested inputs and buttons will be disabled.
    */
   disabled: PropTypes.bool,
+  /**
+   * An array of help texts to be displayed.
+   */
+  helpTexts: PropTypes.node,
   /**
    * ID of the root HTML element.
    *

src/components/InputGroup/InputGroup.module.scss

@@ -1,4 +1,4 @@
-// 1. The class name is intentionally singular because it's targeted by other mixins too.
+// 1. The class names are intentionally singular because they are also targeted by other mixins.
 // 2. Use a block-level display mode to prevent extra white space below grouped inputs in Safari.
 // 3. Let wide input groups honor the minimum input width and overflow horizontally without wrapping and distorting
 //    the inputs.
@@ -39,6 +39,7 @@
     }
 
     // 1.
+    .helpText,
     .validationText {
         @include reset.list();
         @include foundation.help-text();

src/components/InputGroup/README.md

@@ -60,13 +60,14 @@ See [API](#api) for all available options.
   Make sure your inputs fit their container, especially on small screens.
 
 - In the background, InputGroup uses the [`fieldset`][fieldset] element. Not
-  only it improves the [accessibility] of the group, it also allows you to make
-  use of its built-in features like disabling all nested inputs or pairing the
-  group with a form outside. Consult [the MDN docs][fieldset] to learn more.
+  only does it improve the [accessibility] of the group, it also allows you to
+  make use of its built-in features like disabling all nested inputs or pairing
+  the group with a form outside. Consult [the MDN docs][fieldset] to learn more.
 
 - InputGroup currently **supports grouping of**
   [TextField](/components/TextField), [SelectField](/components/SelectField),
-  and [Button](/components/Button) components.
+  [FileInputField](/components/FileInputField), and [Button](/components/Button)
+  components.
 
 - To group [Buttons](/components/Button) only, use the
   [ButtonGroup](/components/ButtonGroup) component which is designed
@@ -104,7 +105,7 @@ You can set the `size` property directly on InputGroup to be shared for all
 fields and buttons inside the group. This property is then passed over to
 individual elements. At the same time, it **cannot be overridden** on the
 fields' or buttons' level. While technically possible, from the design point of
-view it's undesirable to group elements of totally different types or sizes.
+view, it's undesirable to group elements of totally different types or sizes.
 
 ## Invisible Label
 
@@ -136,9 +137,9 @@ the input.
 
 ## Horizontal layout
 
-The default vertical layout is very easy to use and work with. However, there
-are situations where horizontal layout suits better — and that's why React UI
-supports this kind of layout as well.
+The default vertical layout is straightforward to use and work with. However,
+there are situations where horizontal layout suits better — and that's why
+React UI supports this kind of layout as well.
 
 ```docoff-react-preview
 <InputGroup
@@ -150,6 +151,57 @@ supports this kind of layout as well.
 </InputGroup>
 ```
 
+## Help Text
+
+You may provide one or more additional help texts to clarify how the input group
+should be filled.
+
+These messages are not semantically tied to the `children` elements, the
+connection should be expressed in textual form in the actual message.
+
+⚠️ Help texts passed to input elements' `helpText` prop are ignored within
+InputGroup.
+
+```docoff-react-preview
+React.createElement(() => {
+  const [fruit, setFruit] = React.useState('apple');
+  const options = [
+    {
+      label: 'Apple',
+      value: 'apple',
+    },
+    {
+      label: 'Pear',
+      value: 'pear',
+    },
+    {
+      label: 'Cherry',
+      value: 'cherry',
+    },
+  ];
+  return (
+    <InputGroup
+      label="Your favourite fruit"
+      helpTexts={[
+        "Choose one or more kinds of fruit to feel happy.",
+      ]}
+    >
+      <SelectField
+        label="Your favourite fruit"
+        onChange={(e) => setFruit(e.target.value)}
+        options={options}
+        value={fruit}
+      />
+      <TextField
+        label="Variety"
+        placeholder="Eg. Golden delicious"
+      />
+      <Button label="Submit" />
+    </InputGroup>
+  );
+})
+```
+
 ## States
 
 ### Disabled State
@@ -169,12 +221,15 @@ Validation states visually present the result of validation of the grouped
 inputs. Input group's validation state is taken from its child inputs. You
 should always **provide validation messages for states other than valid**
 directly through `validationTexts` prop so users know what happened and what
-action they should take or what options they have. These messages are not
-semantically tied to the `children` elements, the connection should be expressed
-in textual form in the actual message. The individual `children` elements must
-not show any `validationText`, they only show their respective `validationState`.
-Validation messages passed to input elements' `validationText` prop will be
-ignored.
+action they should take or what options they have.
+
+These messages are not semantically tied to the `children` elements, the
+connection should be expressed in textual form in the actual message. The
+individual `children` elements must not show any `validationText`, they only
+show their respective `validationState`.
+
+⚠️ Validation messages passed to input elements' `validationText` prop are
+ignored within InputGroup.
 
 👉 While there is a `required` property to visually denote the whole input group
 is required, there is no functional effect as there is no such HTML attribute

src/components/SelectField/SelectField.jsx

@@ -109,7 +109,7 @@ export const SelectField = React.forwardRef((props, ref) => {
             <div className={styles.bottomLine} />
           )}
         </div>
-        {helpText && (
+        {(helpText && !inputGroupContext) && (
           <div
             className={styles.helpText}
             id={id && `${id}__helpText`}
@@ -172,6 +172,9 @@ SelectField.propTypes = {
    *
    * If `key` in the option definition object is set,
    * then `option.key` is used instead of `option.value` in place of `<VALUE>`.
+   *
+   * Help text is never rendered when the component is placed into `InputGroup`. Instead, the `InputGroup`
+   * component itself renders all help texts of its nested components.
    */
   id: PropTypes.string,
   /**

src/components/TextField/TextField.jsx

@@ -84,7 +84,7 @@ export const TextField = React.forwardRef((props, ref) => {
             <div className={styles.bottomLine} />
           )}
         </div>
-        {helpText && (
+        {(helpText && !inputGroupContext) && (
           <div
             className={styles.helpText}
             id={id && `${id}__helpText`}
@@ -132,6 +132,9 @@ TextField.propTypes = {
   fullWidth: PropTypes.bool,
   /**
    * Optional help text.
+   *
+   * Help text is never rendered when the component is placed into `InputGroup`. Instead, the `InputGroup`
+   * component itself renders all help texts of its nested components.
    */
   helpText: PropTypes.node,
   /**