Update and rename LimitedWordTextArea.md to LimitedWordTextarea.md

This commit is contained in:
Angelos Chalaris
2019-02-20 18:22:22 +02:00
committed by GitHub
parent fd813aa738
commit 66878b1a79
2 changed files with 61 additions and 62 deletions

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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 -- >

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### LimitedWordTextarea
Renders a textarea component with a word limit.
Use the `React.useState()` hook to create the `content` and `wordCount` state variables and set their values to `value` and `0` respectively.
Create a method `setFormattedContent`, which uses `String.prototype.split(' ')` to turn the input into an array of words and check if the result of applying `Array.prototype.filter(Boolean)` has a `length` longer than `limit`.
If the afforementioned `length` exceeds the `limit`, trim the input, otherwise return the raw input, updating `content` and `wordCount` accordingly in both cases.
Use the `React.useEffect()` hook to call the `setFormattedContent` method on the value of the `content` state variable.
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 call `setFormattedContent` with the value of `event.target.value`.
```jsx
function LimitedWordTextarea({ rows, cols, value, limit }) {
const [content, setContent] = React.useState(value);
const [wordCount, setWordCount] = React.useState(0);
const setFormattedContent = text => {
let words = text.split(" ");
if (words.filter(Boolean).length > limit) {
setContent(
text
.split(" ")
.slice(0, limit)
.join(" ")
);
setWordCount(limit);
} else {
setContent(text);
setWordCount(words.filter(Boolean).length);
}
};
React.useEffect(() => {
setFormattedContent(content);
}, []);
return (
<div>
<textarea
rows={rows}
cols={cols}
onChange={event => setFormattedContent(event.target.value)}
value={content}
/>
<p>
{wordCount}/{limit}
</p>
</div>
);
}
```
```jsx
ReactDOM.render(
<LimitedWordTextArea limit={5} value='Hello there!' />,
document.getElementById('root')
);
```
<!-- tags: input,state,effect -->
<!-- expertise: 0 -->