const mapStateToProps = state => {
    return {
        profile: state.profileReducer.profile
    }
}

const mapDispatchToProps = dispatch => {
    return {
        dispatch: action => {
            dispatch(action)
        }
    }
}

...

handleConnection = () => {
    const { profile } = this.props

    this.props.dispatch({ type: 'CONNECT_USER' })

}

...

export default connect(mapStateToProps, mapDispatchToProps)(LoginPage)

import io from 'socket.io-client'

const host = [SERVER_URL]

const socketConnection = io.connect(host, {path: [PATH], secure: true})

const initialState = {
    profile: {
        token: null,
        username: '',
        password: ''
    }
}

function profileReducer(state = initialState, action) {
    switch(action.type) {

        ...

        case 'CONNECT_USER':
            let tempProfile = {...state.profile}

            socketConnection.emit('login', tempProfile.username + ';' + tempProfile.password)

            socketConnection.on('check', msg => {
                if (msg !== null && msg !== '')
                    tempProfile.token = msg

                return {
                    ...state,
                    profile: tempProfile
                }
            })

            return state

        ...
    }
}