feat(CharacterCount): Add new component CharacterCount (#383)

src/components/forms/CharacterCount/CharacterCount.stories.tsx

@@ -0,0 +1,98 @@
+import React from 'react'
+import { CharacterCount } from './CharacterCount'
+import { Form } from '../Form/Form'
+import { FormGroup } from '../FormGroup/FormGroup'
+import { Label } from '../Label/Label'
+
+export default {
+  title: 'Forms/CharacterCount',
+  parameters: {
+    info: `
+USWDS 2.0 Character count component
+
+Source: https://designsystem.digital.gov/components/form-controls/#character-count
+`,
+  },
+}
+const mockSubmit = (): void => {
+  /* mock submit fn */
+}
+
+export const textInput = (): React.ReactElement => (
+  <Form onSubmit={mockSubmit}>
+    <FormGroup>
+      <Label htmlFor="with-hint-input">Text input</Label>
+      <span id="with-hint-input-hint" className="usa-hint">
+        This is an input with a character counter.
+      </span>
+      <CharacterCount
+        id="with-hint-input"
+        name="with-hint-input"
+        aria-describedby="with-hint-input-info with-hint-input-hint"
+        maxLength={25}
+      />
+    </FormGroup>
+  </Form>
+)
+
+export const textarea = (): React.ReactElement => (
+  <Form onSubmit={mockSubmit}>
+    <FormGroup>
+      <Label htmlFor="with-hint-textarea">Textarea</Label>
+      <span id="with-hint-textarea-hint" className="usa-hint">
+        This is a textarea with a character counter.
+      </span>
+      <CharacterCount
+        id="with-hint-textarea"
+        name="with-hint-textarea"
+        maxLength={50}
+        isTextArea
+        rows={2}
+        aria-describedby="with-hint-textarea-info with-hint-textarea-hint"
+      />
+    </FormGroup>
+  </Form>
+)
+
+export const withCustomCharacterCount = (): React.ReactElement => {
+  const customEmojiCharacterCount = (text: string): number => {
+    const starCount = (text.match(/⭐️/g) || []).length
+    return Array.from(text).length - starCount * 2
+  }
+
+  const customEmojiMessage = (count: number, maxCount: number): string => {
+    const remainingCount = maxCount - count
+    if (remainingCount >= 0) return `${remainingCount} of ${maxCount} remain`
+  }
+
+  const twitterStyleMessage = (count: number, maxCount: number): string => {
+    if (maxCount - count < 5) return `${maxCount - count}`
+  }
+
+  return (
+    <Form onSubmit={mockSubmit}>
+      <FormGroup>
+        <Label htmlFor="character-count-input">Custom - stars are free</Label>
+        <CharacterCount
+          id="character-count-input"
+          name="characterCountInput"
+          defaultValue="⭐️⭐️⭐️"
+          getCharacterCount={customEmojiCharacterCount}
+          getMessage={customEmojiMessage}
+          maxLength={10}
+        />
+      </FormGroup>
+      <FormGroup>
+        <Label htmlFor="character-count-textarea">Custom - Twitter style</Label>
+        <CharacterCount
+          id="character-count-textarea"
+          name="characterCountTextArea"
+          isTextArea
+          defaultValue="In most cases, the text content of a Tweet can contain up to 280 characters or Unicode glyphs. The exact definition of which characters have weights greater than one character is found in the configuration file for the twitter-text Tweet parsing library. This is just an example using regex😇"
+          maxLength={280}
+          getMessage={twitterStyleMessage}
+        />
+      </FormGroup>
+    </Form>
+  )
+}