我试图向Node发送一个React状态，其思想是当用户输入邮政编码时，

1. React查找地质坐标，
2. 将其存储在状态
3. React将此状态发送到节点代码中的open weather api，
4. 节点然后获取天气数据并发回响应。

我做了1，2，4，但3给了我一个错误。 下面是需要接收React状态的节点代码:

const axios = require('axios');
const dotenv = require('dotenv');
dotenv.config();

module.exports = (app) => {

    app.get('/search-location', (req, res) => {
        res.send('This is the search location page')
    });

    app.post('/search-location', (req, res) => {

        let baseUrl = `http://api.openweathermap.org/data/2.5/weather?`,
            apiKey = `&appid=${process.env.REACT_APP_WEATHER_API_KEY}`,
            coordinates = `lat=` + coord[0] + `&lon=` + coord[1], // here I need the coordinates from React state
            apiUrl = baseUrl + coordinates + apiKey;
        axios.get(apiUrl)
            .then(response => {
                res.json(response.data);
                console.log(response);
            })
            .catch(error => {
                res.redirect('/error');
                console.log(error);
                console.log('search location error')
            });
    });
}

下面是将状态发送到Node的React方法（我使用一个伪coord变量进行测试）:

sendToNode() {
    
    let coord = {
        longitude: 50,
        latitude: -2.1
    }

    axios.post('http://localhost:4000/search-location', coord)
        .then((response) => {
            console.log(response);
        }, (error) => {
            console.log(error); // here is line 36 where the 404 error logged in console
        });
}

我在谷歌上搜索了很多，上面的方法看起来是正确的，但是我在Chrome控制台中发现了以下错误:

xhr.js:178 GET http://localhost:4000/error 404 (Not Found)
WeatherTile.js:36 Error: Request failed with status code 404
    at createError (createError.js:16)
    at settle (settle.js:17)
    at XMLHttpRequest.handleLoad (xhr.js:61)

为什么会发生这种情况？我该如何解决它？ 提前谢谢你！

更新I将节点代码更改为:

......
app.post('/search-location', (req, res) => {
        let coord = req.body.coord;
        let baseUrl = `http://api.openweathermap.org/data/2.5/weather?`,
            apiKey = `&appid=${process.env.REACT_APP_WEATHER_API_KEY}`,
            coordinates = `lat=` + coord[0] + `&lon=` + coord[1],
            /* coordinates = `lat=` + `51.5842` + `&lon=` + `-2.9977`, */
            apiUrl = baseUrl + coordinates + apiKey;
......

现在我在Chrome控制台中得到了这个错误:

POST http://localhost:4000/search-location 500 (Internal Server Error)
WeatherTile.js:36 Error: Request failed with status code 500
    at createError (createError.js:16)
    at settle (settle.js:17)
    at XMLHttpRequest.handleLoad (xhr.js:61)