For Class Based Components
<!-- begin snippet: js hide: false console: true babel: false -->
<!-- language: lang-js -->
import React from "react";
import { TextField } from "@material-ui/core";
import { withStyles, createStyles } from "@material-ui/core/styles";
const commonStyles = (theme) =>
createStyles({
root: {},
warningStyles: {
"& .MuiFormLabel-root.Mui-error": {
color: "orange !important"
},
"& .MuiInput-underline.Mui-error:after": {
borderBottomColor: "orange !important"
},
"& .MuiFormHelperText-root.Mui-error": {
color: "orange !important"
}
}
});
class DemoComponent extends React.Component {
render() {
const { classes } = this.props;
const _text1HasWarning = false;
const _text2HasWarning = true;
const _text3HasWarning = false;
return (
<>
<TextField
error={false}
className={_text1HasWarning ? classes.warningStyles : null}
value="Valid Value"
variant="standard"
label="Valid label"
helperText="Valid helper text"
/>
<br />
<br />
<br />
<TextField
error={true}
className={_text2HasWarning ? classes.warningStyles : null}
value="warning value"
variant="standard"
label="warning label"
helperText="warning helper text"
/>
<br />
<br />
<br />
<TextField
error={true}
className={_text3HasWarning ? classes.warningStyles : null}
value="error value"
variant="standard"
helperText="error helper text"
label="error label"
/>
</>
);
}
}
export default withStyles(commonStyles)(DemoComponent);
<!-- language: lang-html -->
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<!-- end snippet -->
[Output][1]
[1]: https://i.stack.imgur.com/GVC9k.png
React circa 2020
----------------
In the `onClick` callback, call the [state hook's][1] setter function to update the state and re-render:
<!-- begin snippet: js hide: false console: true babel: true -->
<!-- language: lang-js -->
const Search = () => {
const [showResults, setShowResults] = React.useState(false)
const onClick = () => setShowResults(true)
return (
<div>
<input type="submit" value="Search" onClick={onClick} />
{ showResults ? <Results /> : null }
</div>
)
}
const Results = () => (
<div id="results" className="search-results">
Some Results
</div>
)
ReactDOM.render(<Search />, document.querySelector("#container"))
<!-- language: lang-html -->
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.13.1/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.13.1/umd/react-dom.production.min.js"></script>
<div id="container">
<!-- This element's contents will be replaced with your component. -->
</div>
<!-- end snippet -->
[JSFiddle][2]
React circa 2014
----------------
The key is to update the state of the component in the click handler using `setState`. When the state changes get applied, the `render` method gets called again with the new state:
<!-- begin snippet: js hide: false console: true babel: true -->
<!-- language: lang-js -->
var Search = React.createClass({
getInitialState: function() {
return { showResults: false };
},
onClick: function() {
this.setState({ showResults: true });
},
render: function() {
return (
<div>
<input type="submit" value="Search" onClick={this.onClick} />
{ this.state.showResults ? <Results /> : null }
</div>
);
}
});
var Results = React.createClass({
render: function() {
return (
<div id="results" className="search-results">
Some Results
</div>
);
}
});
ReactDOM.render( <Search /> , document.getElementById('container'));
<!-- language: lang-html -->
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.6.2/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/15.6.2/react-dom.min.js"></script>
<div id="container">
<!-- This element's contents will be replaced with your component. -->
</div>
<!-- end snippet -->
[JSFiddle][3]
[1]: https://reactjs.org/docs/hooks-state.html
[2]: https://jsfiddle.net/khx30pnv/
[3]: http://jsfiddle.net/kb3gN/15084/
