react-intl message lookup bubbling, see: https://github.com/yahoo/react-intl/issues/1109

example

<IntlProvider
    locale={locale}
    messages={messages.app}
>
    <NestedIntlProvider
        locale={locale}
        messages={messages.greeting}
    >
        <div>
            <FormattedMessage
                id="app.title"
                defaultMessage="React Intl Nested Messages Example"
            />
            <FormattedMessage
                id="greeting.welcome_message"
                defaultMessage="Welcome"
            />
        </div>
    </NestedIntlProvider>
</IntlProvider>

NestedIntlProvider.js

import React from 'react'
import { injectIntl, IntlProvider } from 'react-intl'

/**
 * Merges previous and current messages
 * See: https://github.com/yahoo/react-intl/issues/1109
 */
const NestedIntlProvider = ({intl, ...props}) => {
  const { messages, ...otherProps } = props
  const nestedMessages = {
    ...intl.messages,
    ...messages
  }
  return <IntlProvider messages={nestedMessages} {...otherProps} />
}


export default injectIntl(NestedIntlProvider)