flipper/docs/styling-components.md

id, title, sidebar_label

id	title	sidebar_label
styling-components	Styling Components	Styling Components

We use a styled-component based approach to styling our views. This means styles are defined in JavaScript and are written as CSS-stylesheets to the DOM. A component and its styles are coupled. Styled components can extend another to inherit their styles.

Basic tags

For basic building blocks (views, texts, ...) you can use the styled object.

import {styled} from 'flipper';

const MyView = styled.view({
  fontSize: 10,
  color: colors.red
});
const MyText = styled.text({ ... });
const MyImage = styled.image({ ... });
const MyInput = styled.input({ ... });

But you can use any other HTML-tags like this:

styled.customHTMLTag('canvas', { ... });

Extending Flipper Components

It's very common for components to require customizing Flipper's components in some way. For example changing colors, alignment, or wrapping behavior. There is a extends method on all styled components which allows adding or overwriting existing style rules.

For these use cases when a styled component is only used within the context of a single component we encourage declaring it as a inner static instance. This makes it clear where the component is used and avoids polluting the global namespace.

class MyComponent extends Component {
  static Container = FlexRow.extends({
    alignItems: 'center',
  });

  render() {
    return <MyComponent.Container>...</MyComponent.Container>;
  }
}

CSS

The CSS-in-JS object passed to the styled components takes just any CSS rule, with the difference that it uses camel cased keys for the properties. Pixel-values can be numbers, any other values need to be strings.

Dynamic values also can be functions, receiving the react props as argument. (Make sure to add properties passed to a component to the ignoredAttributes array to not be written to the DOM as an attribute.)

const MyView = styled.view(
  {
    fontSize: 10,
    color: props => (props.disabled ? colors.red : colors.black),
  },
  {
    ignoredAttributes: ['disabled'],
  }
);

Pseudo-classes can be used like this:

'&:hover': {color: colors.red}`

Colors

The colors module contains all standard colors used by Flipper. All the available colors are defined in src/ui/components/colors.js with comments about suggested usage of them. And we strongly encourage to use them.