javascript - redux props undefine

Question

I am trying to write a chatting web app. In the following code, if I exclude all the codes pertaining to conversations, it works fine(It's fine if I only loads usernames and try to send a message). But once I added all the codes pertaining to conversations, it keeps popping and error message "this.props.recipients is undefined." But it was working fine before I add any conversation related codes(ie, loadConversations() & conversationList()). I was able to access this.prop.recipients before adding these codes(as can be shown in userList). What am I doing wrong??

import React from 'react';
import { connect, Provider } from 'react-redux';
import fetch from 'isomorphic-fetch';
import * as actions from './actions/index'


class Chat extends React.Component{ 
    constructor(props){
        super(props);
        this.state = {recipientId: '', messageBuffer:'asdfadsfasdf'};
        this.userList = this.userList.bind(this);
        this.changeRecipient = this.changeRecipient.bind(this);
        this.insertText = this.insertText.bind(this);
    }
    componentWillMount(){
        this.props.loadConversations();

        this.props.loadRecipients();
    }

    userList(){
        if(this.props.recipients.length == 0){
            console.log('why??');   
        }
        else{
            console.log('here');
            console.log(this.props.recipients.length)
            return this.props.recipients.map(user=>(<option key = {user._id} value = {user._id}>{user.name}</option>));
        }
    }


    changeRecipient(e){
        e.preventDefault();
        this.setState({recipientId: e.target.value});
    }

    insertText(e){
        e.preventDefault();
        this.setState({messageBuffer:e.target.value});
    }

    newMessage(e){
        e.preventDefault();
        var recipientId = this.state.recipientId;
        if (recipientId ===''){
            recipientId = this.props.recipients[0]._id;
        }
        console.log(recipientId);
        console.log(this.state.messageBuffer);
        fetch('/newMessage',
        {
            headers: {
              'Accept': 'application/json',
              'Content-Type': 'application/json',
              'Authorization' : localStorage.getItem("token"),

            },
            method: "POST",
            body: JSON.stringify({recipient:recipientId, composedMessage:this.state.messageBuffer})
        })
        .then(function(response) {
            console.log(response);
        })
    }

    conversationList(){
        console.log('in conversation list');
        console.log(this.props.conversations.length);
    }

    render(){

        return (
            <div>
                <form onSubmit = {(e) => this.newMessage(e)}>
                    <select name="recipient" onChange = {(e)=> this.changeRecipient(e)}>
                        {this.userList()}
                    </select>
                    <input type = 'text' name = 'composedMessage' onChange = {(e)=> this.insertText(e)}></input>
                    <input type="submit" value="Submit" ></input>
                </form> 
                {this.conversationList}
            </div>)
    }


}

function mapStateToProps(state) {  
    return {recipients: state.recipients, conversations: state.conversations};
}

export default connect(mapStateToProps, actions)(Chat);

here's my action creators

import {LOAD_RECIPIENTS, LOAD_CONVERSATIONS } from './type'

export function loadRecipients(){
    return function(dispatch){
        fetch("/getRecipients",
        {
            headers: {
              'Accept': 'application/json',
              'Content-Type': 'application/json',
              'Authorization' : localStorage.getItem("token")
            },
            method: "GET",
        })
        .then(function(response) {
            return response.json();
        })
        .then(json=>{
            console.log(json.users);
            console.log('load recipients here!!');
            dispatch({type: LOAD_RECIPIENTS, recipients: json.users});
        })
        .catch(err=>{
            console.log(err);
        });
    }
}

export function loadConversations(){
    return function(dispatch){
        fetch("/getConversations",
        {
            headers: {
              'Accept': 'application/json',
              'Content-Type': 'application/json',
              'Authorization' : localStorage.getItem("token")
            },
            method: "GET",
        })
        .then(function(response) {
            return response.json();
        })
        .then(json=>{
            console.log(json.conversations);
            console.log('load conversations here!!');
            dispatch({type: LOAD_CONVERSATIONS , conversations: json.conversations});
        })
        .catch(err=>{
            console.log(err);
        });
    }
}

and here's the reducer

import {LOAD_RECIPIENTS,LOAD_CONVERSATIONS} from '../actions/type.js';

const initial = {recipients:[], conversations:[]}


export default function(state = initial, action){
    switch (action.type){
        case LOAD_RECIPIENTS:
            return {recipients : action.recipients};
            break;
        case LOAD_CONVERSATIONS:
            return {conversations : action.conversations};
            break;
        default:
            return state;
    }
}

here's the error message

stack: "userList@ http://localhost:8000/chatbundle.js:24584:1 \\nrender@ http://localhost:8000/chatbundle.js:24657:7 \\n_renderValidatedComponentWithoutOwnerOrContext/renderedElement<@ http://localhost:8000/chatbundle.js:19501:16 \\nmeasureLifeCyclePerf@ http://localhost:8000/chatbundle.js:18781:12 \\n_renderValidatedComponentWithoutOwnerOrContext@ http://localhost:8000/chatbundle.js:19500:25 \\n_renderValidatedComponent@ http://localhost:8000/chatbundle.js:19527:27 \\n_updateRenderedComponent@ http://localhost:8000/chatbundle.js:19451:31 \\n_performComponentUpdate@ http://localhost:8000/chatbundle.js:19429:5 \\nupdateComponent@ http://localhost:8000/chatbundle.js:19350:7 \\nreceiveComponent@ http://localhost:8000/chatbundle.js:19252:5 \\nreceiveComponent@ http://localhost:8000/chatbundle.js:2755:5 \\n_updateRenderedComponent@ http://localhost:8000/chatbundle.js:19459:7 \\n_performComponentUpdate@ http://localhost:8000/chatbundle.js:19429:5 \\nupdateComponent@ http://localhost:8000/chatbundle.js:19 350:7 \\nperformUpdateIfNecessary@ http://localhost:8000/chatbundle.js:19266:7 \\nperformUpdateIfNecessary@ http://localhost:8000/chatbundle.js:2787:5 \\nrunBatchedUpdates@ http://localhost:8000/chatbundle.js:1399:5 \\nperform@ http://localhost:8000/chatbundle.js:3913:13 \\nperform@ http://localhost:8000/chatbundle.js:3913:13 \\nperform@ http://localhost:8000/chatbundle.js:1338:12 \\nflushBatchedUpdates@ http://localhost:8000/chatbundle.js:1421:7 \\ncloseAll@ http://localhost:8000/chatbundle.js:3979:11 \\nperform@ http://localhost:8000/chatbundle.js:3926:11 \\nbatchedUpdates@ http://localhost:8000/chatbundle.js:20569:14 \\nenqueueUpdate@ http://localhost:8000/chatbundle.js:1449:5 \\nenqueueUpdate@ http://localhost:8000/chatbundle.js:5857:3 \\nenqueueSetState@ http://localhost:8000/chatbundle.js:6051:5 \\nReactComponent.prototype.setState@ http://localhost:8000/chatbundle.js:6663:3 \\nonStateChange@ http://localhost:8000/chatbundle.js:10542:11 \\ndispatch@ http://localhost:8000/chatbundle.js:10848:7 \\n createThunkMiddleware/http://localhost:8000/chatbundle.js:24511:16\\ndispatch@ http://localhost:8000/chatbundle.js:24261:18 \\nloadConversations/http://localhost:8000/chatbundle.js:25207:4\\n"

Answer 1

It turns out there's a mistake in my reducer. I forgot to add in spread operator, so it completely erased the previous state.

it should be

export default function(state = initial, action){
    switch (action.type){
        case LOAD_RECIPIENTS:
            return {...state,recipients : action.recipients};
            break;
        case LOAD_CONVERSATIONS:
            return {...state, conversations : action.conversations};
            break;
        default:
            return state;
    }
}