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    0.8.2 • Public • Published


    Codeship Status for Tiqa/redux-polyglot

    Toolset (actions, reducer, middleware, enhancer, selectors) to help use Polyglot with Redux.


        npm install --save redux-polyglot


    First of all, you need the polyglot reducer in your rootReducer :

    import { createStore, combineReducers } from 'redux';
    import { polyglotReducer } from 'redux-polyglot';
    const rootReducer = combineReducers({
        polyglot: polyglotReducer,
    const store = createStore(rootReducer, {});


    Set the language

    without middleware

    You can use redux-polyglot without his middleware, for this you need the setLanguage() action creator :

    • setLanguage :: (String, Object) -> Action


    import { setLanguage } from 'redux-polyglot';
    store.dispatch(setLanguage('en', { yolo: 'yolo' }));

    second parameter should be polyglot phrases (see polyglot documentation)

    note: if language phrases already exists, this will overwrite the corresponding object state.

    with middleware

    The createPolyglotMiddleware() function allow you to automatically update language and phrases by listening to specific action(s).

    The middleware catches specific action(s), and find the locale in the payload, and then [asynchronously] load the polyglot phrases (with Promise).

    It takes 3 parameters and return a middleware :

    • 1 - actionToCatch :: String | Array<String>
      • the type(s) of the action to catch
    • 2 - getLocale :: Object -> String
      • a function that take the catched action as parameter and return new language.
    • 3 - getPhrases :: String -> Promise Object
      • a function that take the language (as provided by getLocale) and return a Promise of Object ( Object should be polyglot phrases )

    the middleware will catch actionToCatch; note: when a matching action is dispatched, it will return this promise called so you can await on it (pretty useful on SSR)

    import { createStore, combineReducers, applyMiddleware } from 'redux';
    const polyglotMiddleware = createPolyglotMiddleware(
        action => action.payload.locale,
        locale => new Promise(resolve => {
            // perform async here
                hello: 'bonjour',
    const store = createStore(rootReducer, {}, applyMiddleware(polyglotMiddleware));

    you can catch more than one action passing an array of action types:

    const polyglotMiddleware = createPolyglotMiddleware(

    note: if language has not changed, nothing happens.


    with getP() selector

    You can use the getP(state) selector.

    It returns an object with 4 functions inside :

    • t: String -> String : translation (the original polyglot t function)
    • tc: String -> String : translation capitalized
    • tt: String -> String : translation titleized
    • tu: String -> String : translation upper-cased
    • tm: (String -> String) -> String -> String : translation using a custom morphism

    (see polyglot documentation)

    there is an optional parameter to getP(). this is allow you to automatically 'aim' a scope in your phrases object using polyglotScope property.

    for example :

    store.dispatch(setLanguage('en', {
        some: { nested: { data: { hello: 'hello' } } }
    const p = getP(store.getState(), { polyglotScope: 'some.nested.data' });
    console.log(p.tc('hello')) // => will return 'Hello'

    Getting current locale

    getLocale(state) selector returns current language.

    If you use React

    You can use connect() from react-redux, and the getP() selector, to get the p prop in your component.


    p: PropTypes.shape({
        t: PropTypes.func.isRequired,
        tc: PropTypes.func.isRequired,
        tu: PropTypes.func.isRequired,
        tm: PropTypes.func.isRequired,
    translate() enhancer

    props.p can be also be provided easily to a component with the translate enhancer :

    import translate from 'redux-polyglot/translate';
    const DummyComponentWithPProps = translate(DummyComponent);

    you can select a polyglotScope with translate('scope', Component)

    // all this lines return an enhanced Dummy component
    translate('catalog', Dummy); // with polyglotScope
    translate()(Dummy); // curried
    translate('catalog')(Dummy); // curried with polyglotScope.
    translate({ polyglotScope : 'some.nested.data', ownPhrases: 'some.nested.data.hello': 'Hi !', ... })(Dummy); // curried with object configuration.
    get locale in a component

    You can use the getLocale() selector inside a mapStateToProps from react-redux.

    Proptype: locale: PropTypes.string,

    Overwrite phrases

    In some case, you should be able to replace some default phrases by others phrases.

    For doing this, you have to define an object which contains your overwrited phrases. This object is composed of : { 'some.nested.data': 'phrase', ... } where key is the target path you want to replace and value ... the new value.

    with getP() selector

    Simply add ownPhrases property and set the new configuration like above to overwrite :

    store.dispatch(setLanguage('en', {
        some: { nested: { data: { hello: 'hello' } } }
    const p = getP(store.getState(), {
        polyglotScope: 'some.nested.data',
        ownPhrases: { 'some.nested.data.hello': 'Hi !' }
    console.log(p.tc('hello')) // => will return 'Hi !'
    with translate() enhancer

    Instead passing only string as parameter : translate('catalog', Dummy), pass a plain object which contains polyglotScope and ownPhrases properties :

        polyglotScope : 'some.nested.data',
        ownPhrases: { 'some.nested.data.catalog': 'Cars' }
    }, Dummy);
    console.log(p.tc('catalog')) // => will return 'Cars'

    Use polyglot options

    if you want to use onMissingKey, allowMissing or warn polyglot options, you can use the createGetP factory selector to create a custom getP.

    usage :

    import { createGetP } from 'redux-polyglot';
    const options = {
      allowMissing: true,
    export const getP = createGetP(options);

    Please note you cannot use translate hoc with a custom getP selector.


    These folks keep the project moving and are resources for help:


    npm i @cabify/redux-polyglot

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