[React] Styling

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Dynamically Assign Styles

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render() {
    let output = null;

    let buttonStyles = {
      color: 'white',
      backgroundColor: 'green',
      font: 'inherit',
      border: '1px solid blue',
      padding: '8px',
      cursor: 'pointer'
    }
    ...

    if (this.state.show) {
      buttonStyles.backgroundColor = 'red';

      ...
    }

Dynamically Change Classes

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// App.css

.red {
  color: red;
}

.bold {
  font-weight: bold;
}
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let classes  = [];

if (this.state.persons.length <= 2) {
  classes.push('red');
}

if (this.state.persons.length <= 1) {
  classes.push('bold');
}

return (
  <div className="App">
    <button
      onClick={this.toggleHandler}
      style={buttonStyles}>Toggle</button>
    <p className={classes.join(' ')}>Test</p>
    {output}
  </div>
);

Use Radium to render qsuedo class

Install Radium npm install --save radium

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// Component.js

const style = {
  margin: '0 auto',
  '@media (minWidth: 500px)' : {
    width: '450px'
  }
}

// In App.js
import Radium, { StyleRoot } from 'radium';
// To use media queries @media...

render() {
    let output = null;

    let buttonStyles = {
      color: 'white',
      backgroundColor: 'green',
      font: 'inherit',
      border: '1px solid blue',
      padding: '8px',
      cursor: 'pointer',

      ':hover': {
        backgroundColor: 'lightgreen',
        color: 'black'
      }
    }

    if (this.state.show) {
      buttonStyles.backgroundColor = 'red';
      buttonStyles[':hover'] = {
        backgroundColor: 'lightred',
        color: 'black'
      };
    }
    ...

    return (
      <StyleRoot> // Wrap in <StylsRoot>
        <div className="App">
          <button
            onClick={this.toggleHandler}
            style={buttonStyles}>Toggle</button>
          <p className={classes.join(' ')}>Test</p>
          {output}
        </div>
    </StyleRoot>
    );
export default Radium(App);

Use CSS module

  • With CSS modules, you can write normal CSS code and make sure, that it only applies to a given component.
  • Read more here
  • npm run eject
  • In the config/webpack.config.js find test: cssRegex

  • Replace that section with

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    test: cssRegex,
    exclude: cssModuleRegex,
    use: getStyleLoaders({
        importLoaders: 1,
        modules: true,
        localIdentName: '[name]__[local]__[hash:base64:5]'
    }),

  • Restart server

In the App.js

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import classes from './App.css';

return (
  <div className={classes.App}>
    <button
      onClick={this.toggleHandler}
      style={buttonStyles}>Toggle</button>
    <p className={assigned.join(' ')}>Test</p>
    {output}
  </div>
);
  • To use Classes globally: :global .Post { ... }