Я новичок в реакции-нативной и aws appsync.Мы пытаемся отобразить список сообщений. Но когда я запускаю реактив-нативный запуск-android, выдается сообщение об ошибке
TypeError:undefined не является объектом (оценивается как _props.listMessagesQuery.listMessages)
[Ниже приведен URL-адрес скриншота с ошибкой] https://i.stack.imgur.com/b1Wlj.png
Chat.js
import React,{Component} from 'react';
import ChatInput from './ChatInput';
import ChatMessages from './ChatMessages';
import { graphql, compose } from 'react-apollo';
import listMessages from './querys/listMessages';
import createMessage from './querys/createMessage';
import gql from 'graphql-tag';
import {
Platform,
StyleSheet,
Text,
View,
scrollIntoView
} from 'react-native';
class Chat extends Component {
state = {
message: '',
}
render() {
return (
<View className='Chat'>
<ChatMessages
messages={this.props.listMessagesQuery.listMessages || []}
endRef={this._endRef}
/>
<ChatInput
message={this.state.message}
onTextInput={(message) => this.setState({message})}
onResetText={() => this.setState({message: ''})}
onSend={this._onSend}
/>
</View>
);
}
_onSend = () => {
//console.log(`Send: ${this.state.message}`)
this.props.createMessageMutation({
variables: {
text: this.state.message,
sentById: this.props.userId
}
})
}
/*
* AUTO SCROLLING
*/
_endRef = (element) => {
this.endRef = element
}
componentDidUpdate(prevProps) {
// scroll down with every new message
if (prevProps.listMessagesQuery.listMessages !== this.props.listMessagesQuery.listMessages && this.endRef) {
this.endRef.scrollIntoView()
}
}
}
export default compose(
graphql(listMessages, {
options: {
fetchPolicy: 'cache-and-network'
},
props: (props) => ({
posts: props.listMessagesQuery.listMessages && props.listMessagesQuery.listMessages.Message,
})
}))(Chat)
App.js
import React,{ Component} from 'react';
import * as AWS from 'aws-sdk';
import {
Platform,
StyleSheet,
Text,
View
} from 'react-native';
import gql from 'graphql-tag';
import { graphql,compose} from 'react-apollo';
import generateStupidName from 'sillyname';
import localStorage from 'react-native-sync-localstorage';
import Chat from './Chat';
import { Async } from 'react-async-await';
import createPerson from './querys/createPerson';
const CHAT_USER_NAME_KEY = 'CHAT_USER_NAME'
const CHAT_USER_ID_KEY = 'CHAT_USER_ID'
class App extends Component {
async componentDidMount() {
let name = localStorage.getItem(CHAT_USER_NAME_KEY)
if (!name) {
name = generateStupidName()
const result = await this.props.createPersonMutation({
variables: { name }
})
localStorage.setItem(CHAT_USER_NAME_KEY, result.data.createPerson.name);
localStorage.setItem(CHAT_USER_ID_KEY, result.data.createPerson.id);
}
}
render() {
const name = localStorage.getItem(CHAT_USER_NAME_KEY)
const userId = localStorage.getItem(CHAT_USER_ID_KEY)
return (
<View style={styles.container}>
<Chat name={name} userId={userId} />
</View>
);
}
}
// const createPerson =gql`
// mutation createPerson($name:String!){
// createPerson(input :{
// name : $name
// }){
// id
// name
// }
// }
// `
// export default graphql(createPerson,{name:'createPersonMutation'})(App)
export default compose(
graphql(createPerson, {name:'createPersonMutation'}))(App)
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
alignItems: 'center',
backgroundColor: '#F5FCFF',
},
welcome: {
fontSize: 20,
textAlign: 'center',
margin: 10,
},
instructions: {
textAlign: 'center',
color: '#333333',
marginBottom: 5,
},
});
Я не понимаю эту ошибку Пожалуйста, помогите мне. Спасибо!заранее