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December 23, 2018 19:00
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import React from 'react'; | |
import {StyleProp, TextStyle, View, ViewProps, ViewStyle} from 'react-native'; | |
export interface WithClassProps { | |
classNames?: string[]; | |
componentTree?: ComponentTree; | |
style?: StyleProp<TextStyle>; | |
} | |
type ComponentTree = { | |
classNames: string[]; | |
parent?: ComponentTree; | |
}; | |
const satisfiesStyle = (styleKey: string, componentTree: ComponentTree) => { | |
const keys = styleKey.split(' '); | |
let currentComponentTree = componentTree; | |
let i: number; | |
for (i = keys.length - 1; i >= 0; ) { | |
const key = keys[i]; | |
if (!currentComponentTree) { | |
return false; | |
} | |
if (currentComponentTree.classNames && currentComponentTree.classNames.includes(key)) { | |
i--; | |
} | |
currentComponentTree = currentComponentTree.parent; | |
} | |
return i === -1; | |
}; | |
const deriveStyles = (styles: any, componentTree: ComponentTree) => { | |
const dStyles: ViewStyle[] = []; | |
if (componentTree.classNames) { | |
for (const styleKey of Object.keys(styles)) { | |
if (satisfiesStyle(styleKey, componentTree)) { | |
dStyles.push((styles as any)[styleKey]); | |
} | |
} | |
} | |
return dStyles; | |
}; | |
export function withClass<P extends ViewProps>( | |
WrappedComponent: React.ComponentClass<P> | React.FunctionComponent<P> | |
): React.ComponentClass<P & WithClassProps> { | |
return class extends React.Component<P & WithClassProps> { | |
constructor(props: P & WithClassProps) { | |
super(props); | |
this.state = {}; | |
} | |
componentTree: ComponentTree; | |
componentWillMount() { | |
this.componentTree = { | |
parent: this.props.componentTree, | |
classNames: this.props.classNames, | |
}; | |
} | |
componentDidMount() { | |
this.componentTree.parent = this.props.componentTree; | |
this.componentTree.classNames = this.props.classNames; | |
} | |
componentWillUpdate(nextProps: Readonly<P & WithClassProps>): void { | |
this.componentTree.classNames = nextProps.classNames; | |
} | |
componentWillUnmount() {} | |
render() { | |
const {style, children, ...props} = this.props; | |
return ( | |
<CssContext.Consumer> | |
{state => ( | |
<WrappedComponent | |
style={[this.componentTree.classNames && deriveStyles(state, this.componentTree), style]} | |
{...props} | |
> | |
{React.Children.map(children, a => React.cloneElement(a, {componentTree: this.componentTree}))} | |
</WrappedComponent> | |
)} | |
</CssContext.Consumer> | |
); | |
} | |
}; | |
} | |
export const ViewWithClass = withClass(View); | |
const store: {styles: any} = {styles: null}; | |
export const CssContext = React.createContext(store); |
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