[enter image description here](https://i.stack.imgur.com/7dutS.png)Trying to display a blog content in react-native using fetch-api. I am much confused with the syntax as it is becoming complex with related examples I am getting online. The API was locally generated from PHP-PDO/MySQL and I have a url tested on POSTMAN. However, I receive error each time I am trying to display the content using fetch-api and console.log(). 

I have tried to check online for similar problem but it seems ambiguous as problems are different from mine. At a point I thought because I was using map() in my render, so I changed to FlatList. 

ERROR: 

```
This error is located at:
    in VirtualizedList (at FlatList.js:625)
    in FlatList (at Category.js:32)
    in RCTView (at View.js:45)
    in View (at Category.js:31)
    in Category (at App.js:10)
    in RCTView (at View.js:45)
    in View (at App.js:9)
    in App (at renderApplication.js:34)
    in RCTView (at View.js:45)
    in View (at AppContainer.js:98)
    in RCTView (at View.js:45)
    in View (at AppContainer.js:115)
    in AppContainer (at renderApplication.js:33)

import React, { Component } from 'react';
import 
{ Text, 
  View,
  FlatList,
  StyleSheet
} from 'react-native';

export default class Category extends Component {
    constructor(props){
        super(props);
        this.state = {
            data: []
        }
    }
        componentWillMount() {
           const that = this;
            fetchData = async () => {
            const response = await  fetch("http://localhost/rest_api_myblog/api/post/read.php");
            const json = await response.json();
            that.setState({ data: json});
            console.log(json);
          }

          }

          render() {
             return(
               <View style={styles.container}>
                 <FlatList 
                 data={this.state.data}
                 keyExtractor={(x, i) => i}
                 renderItem={({ item }) =>
                 <Text>
                   {`${item.author} ${item.category_name}`}
                 </Text>}
                 />
               </View>
             );

          }
}

```

I want to display post contents