Incontext

Light state management library based on React context API.

Incontext attempts to mimic react-redux interface. While the interface is very similar there some minor differences to watch out, primarily in area of creating Provider's store.

To see how to use incontext in React application see examples/todo. This todo app is virtually copied line by line from redux.js.org website and shows how easy it is to use incontext instead of react-redux.

Installing

This library uses React's context APIs so it requires React 16.3 or higher.

To install incontext:

npm install --save incontext

Manual

Provider

You should wrap your React application with Provider component. Provider component expects store property to be passed to it. Store contains reducers as well as initial state for each reducer.

Use createStore utility function to convert your reducers to proper store object:

import { createStore } from '@iris-platform/incontext';
const store = createStore([Todo, User, Teams]);

Here Todo, User, Teams are reducers. createStore accepts array of reducer objects and converts them to store representation.

import { Provider, createStore } from '@iris-platform/incontext';

const store = createStore([Todo]);

const App = () => (
  <Provider store={store}>
    ...
  </Provider>
);

Reducers

Reducer objects describe how state changes in response to actions.

const initialState = {
  visibilityFilter: SHOW_ALL,
  todos: []
};

const Todo = (state = initialState, action) => {
  switch (action.type) {
    case SET_VISIBILITY_FILTER:
      return {
        ...state,
        visibilityFilter: action.filter
      };

    case ADD_TODO:
      return {
        ...state,
        todos: [
          ...state.todos,
          {
            text: action.text,
            completed: false
          }
        ]
      };

    case TOGGLE_TODO:
      return {
        ...state,
        todos: state.todos.map((todo, index) => {
          if (index === action.index) {
            return {
              ...todo,
              completed: !todo.completed
            };
          }
          return todo;
        })
      };

    default:
      return state;
  }
};

export default Todo;

You will always need to define initialState with initial values. Provider will use these values to set its initial state.

Just like in react-redux we do not mutate the state we copy the state object with updated values.

Actions

Actions are functions that deliver specific payloads to incontext store. Incontext store updates in response to the reducer receiving the new payload from incoming action.

const TodoActions = {
  addTodo: text => {
    return {
      type: ADD_TODO,
      text
    };
  },
  toggleTodo: index => {
    return {
      type: TOGGLE_TODO,
      index
    };
  },
  setVisibilityFilter: filter => {
    return {
      type: SET_VISIBILITY_FILTER,
      filter
    };
  }
};

Components & Containers

Incontext provides the connect utility function for creating container components from presentational components. Below is an example usage. See the redux documentation for a complete discussion of component types.

import { connect } from '@iris-platform/incontext';

const MyComponent = ({ name, onClick }) => (
  <div onClick={onClick}>Hello {name}!</div>
)

const mapStateToProps = state => ({
  name: state.firstName,
})

const mapDispatchToProps = dispatch => ({
  onClick: name => dispatch({ type: 'CLICK', name }),
});

const mergeProps = (stateProps, dispatchProps, ownProps) => ({
  ...stateProps,
  ...dispatchProps,
  onClick: () => dispatchProps.onClick(stateProps.name),
})

export default connect(
  mapStateToProps,
  mapDispatchToProps,
  mergeProps,
)(MyComponent);

Examples

Checkout examples folder for sample usage of incontext.

Contributing

If you find a bug, please create an issue providing instructions to reproduce it. It's always very appreciable if you find the time to fix it. In this case, please submit a PR.