React.js inline style best practices [closed]

I'm aware that you can specify styles within React classes, like this:

const MyDiv = React.createClass({
  render: function() {
    const style = {
      color: 'white',
      fontSize: 200
    };
    
    return <div style={style}> Have a good and productive day! </div>;
  }
});

Should I be aiming to do all styling this way, and have no styles at all specified in my CSS file?

Or should I avoid inline styles completely?

It seems odd and messy to do a little bit of both - two places would need to be checked when tweaking styling.

There aren't a lot of "Best Practices" yet. Those of us that are using inline-styles, for React components, are still very much experimenting.

There are a number of approaches that vary wildly: React inline-style lib comparison chart

All or nothing?

What we refer to as "style" actually includes quite a few concepts:

• Layout — how an element/component looks in relationship to others
• Appearance — the characteristics of an element/component
• Behavior and state — how an element/component looks in a given state

Start with state-styles

React is already managing the state of your components, this makes styles of state and behavior a natural fit for colocation with your component logic.

Instead of building components to render with conditional state-classes, consider adding state-styles directly:

// Typical component with state-classes
<li 
 className={classnames({ 'todo-list__item': true, 'is-complete': item.complete })} />


// Using inline-styles for state
<li className='todo-list__item'
 style={(item.complete) ? styles.complete : {}} />

Note that we're using a class to style appearance but no longer using any .is- prefixed class for state and behavior.

We can use Object.assign (ES6) or _.extend (underscore/lodash) to add support for multiple states:

// Supporting multiple-states with inline-styles
<li 'todo-list__item'
 style={Object.assign({}, item.complete && styles.complete, item.due && styles.due )}>

Customization and reusability

Now that we're using Object.assign it becomes very simple to make our component reusable with different styles. If we want to override the default styles, we can do so at the call-site with props, like so: <TodoItem dueStyle={ fontWeight: "bold" } />. Implemented like this:

<li 'todo-list__item'
 style={Object.assign({},
         item.due && styles.due,
         item.due && this.props.dueStyles)}>

Layout

Personally, I don't see compelling reason to inline layout styles. There are a number of great CSS layout systems out there. I'd just use one.

That said, don't add layout styles directly to your component. Wrap your components with layout components. Here's an example.

// This couples your component to the layout system
// It reduces the reusability of your component
<UserBadge
 className="col-xs-12 col-sm-6 col-md-8"
 firstName="Michael"
 lastName="Chan" />

// This is much easier to maintain and change
<div class="col-xs-12 col-sm-6 col-md-8">
  <UserBadge
   firstName="Michael"
   lastName="Chan" />
</div>

For layout support, I often try to design components to be 100% width and height.

Appearance

This is the most contentious area of the "inline-style" debate. Ultimately, it's up to the component your designing and the comfort of your team with JavaScript.

One thing is certain, you'll need the assistance of a library. Browser-states (:hover, :focus), and media-queries are painful in raw React.

I like Radium because the syntax for those hard parts is designed to model that of SASS.

Code organization

Often you'll see a style object outside of the module. For a todo-list component, it might look something like this:

var styles = {
  root: {
    display: "block"
  },
  item: {
    color: "black"

    complete: {
      textDecoration: "line-through"
    },

    due: {
      color: "red"
    }
  },
}

getter functions

Adding a bunch of style logic to your template can get a little messy (as seen above). I like to create getter functions to compute styles:

React.createClass({
  getStyles: function () {
    return Object.assign(
      {},
      item.props.complete && styles.complete,
      item.props.due && styles.due,
      item.props.due && this.props.dueStyles
    );
  },

  render: function () {
    return <li style={this.getStyles()}>{this.props.item}</li>
  }
});

Further watching

I discussed all of these in more detail at React Europe earlier this year: Inline Styles and when it's best to 'just use CSS'.

I'm happy to help as you make new discoveries along the way :) Hit me up -> @chantastic

The style attribute in React expect the value to be an object, ie Key value pair.

style = {} will have another object inside it like {float:'right'} to make it work.

<span style={{float:'right'}}>Download Audit</span>

Hope this solves the problem

I use inline styles extensively within my React components. I find it so much clearer to colocate styles within components because it's always clear what styles the component does and doesn't have. Plus having the full power of Javascript at hand really simplifies more complex styling needs.

I wasn't convinced at first but after dabbling in it for several months, I'm fully converted and am in process of converting all my CSS to inline or other JS-driven css methods.

This presentation by Facebook employee and React contributor "vjeux" is really helpful as well — https://speakerdeck.com/vjeux/react-css-in-js

The main purpose of the style attribute is for dynamic, state based styles. For example, you could have a width style on a progress bar based on some state, or the position or visibility based on something else.

Styles in JS impose the limitation that the application can't provide custom styling for a reusable component. This is perfectly acceptable in the aforementioned situations, but not when you change the visible characteristics, especially color.

Styling in JSX is very similar to styling in HTML.

HTML Case:

div style="background-color: red; color: white"

JSX Case:

div style={{ backgroundColor: 'red', color: 'white' }}