add limited word text area

snippets/LimitedWordTextArea.md

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+### LimitedWordTextArea
+
+Renders a textarea component with a word limit.
+
+Use the value of the `value` prop to determine the initial `state.content` and `state.wordCount` and the value of the `limit` props to determine the value of `state.limit`.
+Create a method, `handleChange`, which trims the `event.target.value` data if necessary and uses `Component.prototype.setState` to update `state.content` and `state.wordCount`, and bind it to the component's context.
+In the`render()` method, use a`<div>` to wrap both the`<textarea>` and the `<p>` element that displays the character count and bind the `onChange` event of the `<textarea>` to the `handleChange` method.
+
+```jsx
+class LimitedWordTextArea extends React.Component {
+  constructor(props) {
+    super(props);
+    this.state = {
+      content: props.value,
+      wordCount: props.value.split(' ').filter(Boolean).length,
+      limit: props.limit
+    };
+    this.handleChange = this.handleChange.bind(this);
+  }
+
+  handleChange(event) {
+    let newContent = event.target.value;
+
+    if (newContent.split(' ').filter(Boolean).length > this.state.limit) {
+      newContent = newContent
+        .split(' ')
+        .splice(0, this.state.limit)
+        .join(' ');
+    }
+    this.setState(state => ({
+      content: newContent,
+      wordCount: newContent.split(' ').filter(Boolean).length
+    }));
+  }
+  render() {
+    return (
+      <div>
+        <textarea
+          rows={this.props.rows}
+          cols={this.props.cols}
+          onChange={this.handleChange}
+          value={this.state.content}
+        >
+        </textarea>
+        <p>{this.state.wordCount} / {this.props.limit}</p>
+      </div>
+    );
+  }
+}
+```
+
+```jsx
+ReactDOM.render(
+  <LimitedWordTextArea limit={5} value='Hello there!' />,
+  document.getElementById('root')
+);
+```
+
+< !--tags: input,state,class -- >
+
+< !--expertise: 0 -- >
+