react-state-hoc

React state component (higher-order)

A React higher-order component for abstracting away state

Keep your components simple, testable, and composable by using higher-order components. This higher-order component will abstract state away from components, so you can keep using functional stateless components.

Installation

npm install --save react-state-hoc
# or 
yarn add react-state-hoc

API

withState(initialState, mapSetStateToProps?, mergeProps?)(BaseComponent)

Wraps your BaseComponent with a stateful component, passing the state into the BaseComponent as props. By default, state will be spread into the component's props, plus the setState function is passed through. If you specify a mapSetStateToProps function, setState will not be passed through.

Two optional arguments allow you to a) define state creators, and b) customise which props are passed into the BaseComponent.

• initialState can be either:

  • An object, to be used as the component's initial state.

    withState({ visible: true })(BaseComponent)

  • A function, which maps initial props to initial state.

    withState(props => ({ visible: props.visible }))(BaseComponent)

• mapSetStateToProps can be either:

  • An object, containing state creators. Each state creator is a function which maps input arguments to new state. State creators are a convenient shorthand which automatically binds setState into smaller functions. Functions can also be provided as well as objects: they are supported by setState (see https://reactjs.org/docs/react-component.html#setstate)

    withState(
        { visible: true },
        { setVisibility: visible => ({ visible }) }
    )(BaseComponent)

  • A function, mapping initialProps and setState to state creators.

    withState({ state: null }, initialProps => setState => ({
        setValue: value => setState({
            someState: initialProps.mapValue(value)
        })
    }))(BaseComponent)

    Default:

    () => setState => ({ setState })
     

• mergeProps: A function mapping the current props, state and stateCreators into the BaseComponent's props.

  withState(
      { visible: true },
      { setVisibility: visible => ({ visible }) },
      (state, stateCreators, props) => ({
          ...state,
          ...stateCreators
          // deliberately not passing props through to BaseComponent
      })
  )(BaseComponent)

  Default:

  (props, state, stateCreators) => ({ ...props, ...state, ...stateCreators })

Example

import React from 'react'
import ReactDOM from 'react-dom'
import withState from 'react-state-hoc'
 
function StatelessButton({ counter, setCounter }) {
    return (
        <button onClick={() => setCounter(counter + 1)}>
            Clicked {counter} times.
        </button>
    )
}
 
const mapSetStateToProps = () => setState => ({
    setCounter: counter => setState({ counter })
})
 
const StatefulButton1 = withState({ counter: 0 }, mapSetStateToProps)(
    StatelessButton
)
 
const StatefulButton2 = withState({ counter: 10 }, mapSetStateToProps)(
    StatelessButton
)
 
ReactDOM.render(
    <div>
        <StatefulButton1 />
        <StatefulButton2 />
    </div>,
    document.getElementById('app')
)