cf-style-container

cf-style-container

Cloudflare Style Container

Set of high order components and other helpers for fela based applications.

Installation

$ npm install cf-style-container

Aliased functions from fela and react-fela

We proxy/alias some useful functions from fela without changing their behaviour. See the original documentation for more details. We wrap all Fela APIs so we can eventually switch Fela to a different CSS in JS lib if ever needed.

• combineRules
• connect
• ThemeProvider

createComponent(rule, [type])

Very similar to createComponent from react-fela. However, it automatically adds PropTypes from [type] in case that it is a React Component.

You should use this HOC every time when you want to use Fela in your component and you need only one className (one rule function).

import React from 'react';
import PropTypes from 'prop-types';
import { createComponent } from 'cf-style-container';

const styles = ({ theme, size }) => ({
  fontWeight: theme[`fontWeight${size}`],
  fontSize: theme[`fontSize${size}`],
  lineHeight: theme[`lineHeight${size}`],
  marginTop: theme[`marginTop${size}`]
});

const Heading = ({ size, className, children }) => {
  const tagName = 'h' + size;
  return React.createElement(tagName, { className }, children);
};

Heading.propTypes = {
  size: PropTypes.oneOf([1, 2, 3, 4, 5, 6]).isRequired,
  className: PropTypes.string.isRequired,
  children: PropTypes.node
};

export default createComponent(styles, Heading);

createComponentStyles(rules, Component)

Useful when you need multiple classNames (and rules) in one component.

import React from 'react';
import PropTypes from 'prop-types';
import { createComponentStyles } from 'cf-style-container';

const mainStyles = ({ theme }) => ({
  margin: theme.main.margin,
  padding: theme.main.padding,
});

const legendStyles = ({ theme }) => ({
  padding: theme.legend.padding,
  marginBottom: theme.legend.marginBottom,
  borderBottom: theme.legend.borderBottom,
});

const FormFieldset = ({ legend, styles }) => (
  <fieldset className={styles.mainStyles}>
    <legend className={styles.legendStyles}>
      {legend}
    </legend>
  </fieldset>
);

FormFieldset.propTypes = {
  styles: PropTypes.object.isRequired,
  legend: PropTypes.string.isRequired
};

export default createComponentStyles({ mainStyles, legendStyles }, FormFieldset);

Notice that rules are now an object. The names you chose will be used for classNames accessible as styles.mainStyles and styles.legendStyles in this case.

applyTheme(Component, ...themes)

And HOC that ties a Fela component with the theme (adds the theme to its context). The themes can be functions that takes a baseTheme and returns a new theme, or just an object.

import HeadingUnstyled from './Heading';
import HeadingTheme from './HeadingTheme';

import { applyTheme } from 'cf-style-container';

// overrides HeadingTheme fontWeight1
const CustomTheme = () => { fontWeight1: 600 };

const Heading = applyTheme(HeadingUnstyled, HeadingTheme, CustomTheme);

// themed component
<Heading />

mergeTheme(baseTheme, ...themes)

applyTheme() calls this method internally to merge all themes. The returned value is a seamless-immutable object. It has a theme key that contains the merged themes, thus it is suitable for passing down to style functions. The types of baseTheme and themes are the same as applyTheme()'s.

import { variables } from 'cf-style-const';
import { TableUnstyled, TableTheme } from 'cf-component-table';

import { applyTheme, mergeTheme } from 'cf-style-container';

// You can save this theme and pass it around, you can also apply it to a component.
const MyTableTheme = mergeTheme(variables, TableTheme, {color: 'blue'});
...
const MyTable = applyTheme(TableUnstyled, MyTableTheme);

mapChildren(children, callback)

Convenient function that wraps React.Children. This function differs from React.Children.map() in that the children list is turned into an array first, and the callback is invoked as callback(child, index, children). The callback's result value is then mapped to the returned array of mapChildren.

class TableRow extends React.Component {
  render() {
    <tr>
      {mapChildren(this.props.children, (child, index) =>
         React.cloneElement(child, {key: index}))}
    </tr>
  }
}

filterProps(obj, filter)

filterNone(obj)

filterStyle(obj)

filterStyle() filters out the style entry from the object. Used to blacklist the style props from propagating to underlying react-dom element when spreading props.

filterNone() filters out all the entries in the object that have undefined values. This function is useful to make the style objects mergeable and composable, as any key with undefined value will overwrite the previous object of the same key. This is often not the desired result.

filterProps() is the underlying machinary that all other filter function are implemented with. It's essentially a reduce on the list of pairs of enumerable object properties and their keys. The filter(key, value, accum) callback will be invoked with the current key, value and accumulated value for each pair. Useful to blacklist object keys.

All filter functions are composible.

import { filterNone, filterProps } from 'cf-style-container';

filterNone(
  filterProps({
    border: undefined,
    color: 'blue',
    border: '1px solid black'
  }, (key, value, accum) => {
    if (key === 'border') return accum;
    else accum[key] = value;
    return accum;
  })
);

// Returns

// {color: 'blue'}