网络请求失败反应本机EXPO API POST错误

Question

嗨，我正在尝试使用Express和Node JS向我的Mongo DB发布一些数据，并且我会遇到以下错误，但是Postman的数据正常，我正在尝试将缓冲区数据保存到我的MongoDB

网络请求

中，node_modules \ Whatwg-fetch 失败了\ dist \ fetch.umd.js：535：17在settimeout $ grognn_0中 在node_modules \ react-native \ libraries \ core \ timers \ jstimers.js：123：14 in _calltimer 在node_modules \ react-native \ libraries \ core \ timers \ jstimers.js：379：16中 在node_modules \ react-native \ libraries \ batchedbridge \ messagequeue.js：414：4 in __callFunction 在node_modules \ react-native \ libraries \ batchedbridge \ messagequeue.js：113：6中 在node_modules \ react-native \ libraries \ batchedbridge \ messagequeue.js：365：10 in __Guard 在node_modules \ react-native \ libraries \ batchedbridge \ messagequeue.js：112：4 in CallFunctionReturnFlushedQueue

这是我的前端代码

frontend.js

import {
  View,
  Text,
  TextInput,
  Image,
  TouchableOpacity,
  StyleSheet,
  ScrollView,
  Picker,
  Platform,
  Alert,
  input,
  //fetch
} from "react-native";

//const bodyParser = require('body-parser')
//router.use(bodyParser.json());
//router.use(bodyParser.urlencoded({ extended: true }));


import React, { Component } from "react";
import axios from "axios";
import * as ImagePicker from 'expo-image-picker';
//import ImagePickerExample from "../components/CameraFunc";
import Constants from "expo-constants";
import * as FileSystem from 'expo-file-system';



export default class Sellnow extends Component {
  constructor(props) {
    super(props);
    this.onChangePetName = this.onChangePetName.bind(this);
    this.onChangePetTitle = this.onChangePetTitle.bind(this);
    this.onChangePetContact = this.onChangePetContact.bind(this);
    this.onChangePetPrice = this.onChangePetPrice.bind(this);
    this.onChangePetDescription = this.onChangePetDescription.bind(this);
    this.onValueChangeCat= this.onValueChangeCat.bind(this);
    this.onValueChangeCity= this.onValueChangeCity.bind(this);
    this.onFileChange = this.onFileChange.bind(this);
   // this.pickImage = this.pickImage.bind(this);
    this.onSubmit = this.onSubmit.bind(this);
    // State
    this.state = {
      name: "",
      title: "",
      contact: "",
      price: "",
      description: "",
      selectedcat:"",
      selectedcity:"",
      imgforsell:"",

      //collection categories
      category: [
        
        {
          itemName: "Select Category...."
        },
        {
          itemName: "Pets Food"
        },
        {
          itemName: "Pets Products"
        },
        {
          itemName: "Pets Accessories"
        }
      ],

      // cities category
      cityCategory:[


        {
          itemName: "Select City...."
        },
        {
          itemName: "Islamabad"
        },
        {
          itemName: "Rawalpindi"
        },
        {
          itemName: "Lahore"
        },
        {
          itemName: "Peshawar"
        },
        {
          itemName: "Karachi"
        },
        {
          itemName: "Quetta"
        }

      ]
    };
  }


  /*componentDidMount() {
    axios.get('http://localhost:3000/PetsBazar/pets/' )
      .then(res => {
        this.setState({
          name: res.data.name,
          title: res.data.title,
          contact: res.data.contact
        });
      })
      .catch((error) => {
        console.log(error);
      })
  }*/
  onChangePetName(e) {
    this.setState({ name: e.target.value });
  }
  onChangePetTitle(e) {
    this.setState({ title: e.target.value });
  }
  onChangePetContact(e) {
    this.setState({ contact: e.target.value });
  }
  onChangePetPrice(e) {
    this.setState({ price: e.target.value });
  }
  onChangePetDescription(e) {
    this.setState({ description: e.target.value });
  }
  // categories function
  onValueChangeCat(e) {
    this.setState({ selectedcat: e.targetvalue })
  }

  // city function
  onValueChangeCity(e) {
    this.setState({ selectedcity: e.targetvalue })
  }

  onFileChange(e) {
    this.setState({ imgforsell: e.targetvalue})}

  // uploading Image


  _getPhotoLibrary = async () => {
    let result = await ImagePicker.launchImageLibraryAsync({
      allowsEditing: true,
      base64: true,
      exif: true,
      aspect: [4, 3]
    });

    

    if (!result.cancelled) {
      this.setState({ imgforsell: result });
      
      
    }
    this.props.navigation.setParams({
      imgforsell: this.state.imgforsell
    });
  };



  onSubmit  (e) {
    e.preventDefault();
    /*const petsObject = {
      name: this.state.name,
      title: this.state.title,
      contact: this.state.contact,
      price: this.state.price,
      description: this.state.description,
      selectedcat:this.state.selectedcat,
      selectedcity:this.state.selectedcity,
      imgforsell:this.state.imgforsell
      };
*/
      const formData = new FormData();
      /*formData.append( 'imgforsell', {
    
       // name: new Date() + '_profile',
        uri: this.state.imgforsell,
        type: 'image/jpg',
       
      });*/

      
      formData.append("name", this.state.name);
      formData.append("title", this.state.title);
      formData.append("contact", this.state.contact);
      formData.append("price", this.state.price);
      formData.append("description", this.state.description);
      formData.append("selectedcat", this.state.selectedcat);
      formData.append("selectedcity", this.state.selectedcity);

      formData.append("imgforsell", this.state.imgforsell);


      
      


      fetch(
        `"http://${
          Platform.OS === "android" ? " 192.168.10.11" : "localhost"
        }:4000/pets/addpets"`,
        //'http://http://10.0.2.2:4000/pets/addpets',
       
        {
          method: "POST",
          body: formData,
      //   headers: {
        //  "content-Type": "application/json"
     // },
      //body:JSON.stringify({formData})
          
          
         // headers:{"Content-type":"application/json"}
        }
      )
        .then((res) => {
          if (!res.ok) {
            return Promise.reject(res);
          }
          return res.json();
        })
        .then((data) => {
          console.log(data);
        })
        .catch((err) => {
          console.error(err);
        })
        .finally(() => {
          this.setState({
            name: "",
            title: "",
            contact: "",
            price: "",
            description: "",
            selectedcat: "",
            selectedcity: "",
            imgforsell: "",
          });
        });


      /*  axios
  .post(
    `http://${
      Platform.OS === "android" ? "192.168.10.11" : "localhost"
    }:4000/pets/addpets`,
    formData
  )
  .then(({ data }) => {
    console.log(data);
  })
  .catch((err) => {
    console.error(err.toJSON());
    // res.status(500).json(err)