Context in "stateless" component?

Question

I have the following code in a component and I would like a stateless component to access this part of code:

Main component:

function createApp(store, communityIds) {
const App = React.createClass({

    childContextTypes: {
        localizedString: React.PropTypes.func,
    },

    getChildContext: function() {
        return {
            localizedString: function(key, fallback) {
                return getKey(key, fallback);
            },
        };
    },

    render: function() {
        return (
            <Provider store={store}>
                <Client communityIds={communityIds}/>
            </Provider>
        );
    },
});

return <App/>;
}

Stateless:

export default () => (dispatch, getState) => {
    const state = getState();

    const token = state.user.get('token');

    if (!token) {
        throw new Error('test'); // this.context.localizedString does not work
    }
}

Answer 1

What you have provided under your definition of "Stateless:" function is not what a Stateless function is. You have provided your action creator as a thunk. I assume you wanted to insert the code for your Client component instead. To access context in a stateless component, your Client component would do something like this (which is documented here)

const Client = (props, context) => {   
    return  <div >{context.localizedString("someKey", "someFallback")} </div>
}

Client.contextTypes = {
    localizedString: React.PropTypes.func
}

export default Client

Answer 2

I had the same question. The modern way (in 2019) is to use hook useContext(contextName). Docs: https://reactjs.org/docs/hooks-reference.html#usecontext

  const dumbComp = (props) => { 
       const context = useContext(contextName);
          return(
             <div>
             ...
          </div>
       );
    }

Answer 3

Use second parameter of stateless component

const MyStatelessComponent = (props, context) => { 
   const onGoButtonClick = () => {
      context.router.push('https://www.google.co.in');
   };

   return(
      <div>
         <button onClick={() => onButtonClick()}>
            {props.buttonName}
         </button>
      </div>
   );
}

MyStatelessComponent.propTypes = {
   buttonName: PropTypes.string.isRequired,
};

MyStatelessComponent.contextTypes = {
   router: React.PropTypes.object.isRequired,
};

export default MyStatelessComponent;

Answer 4

Another solution is a self invoking function:

export default (Component=>(
  Component.contextTypes = {
    localizedString: React.PropTypes.func
  }) && Component
)((props, context)=>{
  return  <div>{context.localizedString("someKey", "someFallback")}</div>
})

Or if you define the contextTypes separately to reuse it, you could do:

//addContextTypes.js
export default function(Component){
  return (Component.contextTypes = {
    localizedString: React.PropTypes.func
  }) && Component
}

//component.jsx
import addContextTypes from './addContextTypes'
export default addContextTypes((props, context)=>{
  return  <div>{context.localizedString("someKey", "someFallback")}</div>
})