似乎找不到错误所在

Question

我一直在开发一个普通的堆栈应用程序，一切都很好，直到这个突然出现。

SyntaxError: Unexpected token } in JSON at position 23
    at JSON.parse (<anonymous>)
    at parse (C:\Users\Mushood Hanif\Documents\Work\Task-Manager\api\node_modules\body-parser\lib\types\json.js:89:19)
    at C:\Users\Mushood Hanif\Documents\Work\Task-Manager\api\node_modules\body-parser\lib\read.js:121:18
    at invokeCallback (C:\Users\Mushood Hanif\Documents\Work\Task-Manager\api\node_modules\raw-body\index.js:224:16)
    at done (C:\Users\Mushood Hanif\Documents\Work\Task-Manager\api\node_modules\raw-body\index.js:213:7)
    at IncomingMessage.onEnd (C:\Users\Mushood Hanif\Documents\Work\Task-Manager\api\node_modules\raw-body\index.js:273:7)
    at IncomingMessage.emit (events.js:333:22)
    at endReadableNT (_stream_readable.js:1220:12)
    at processTicksAndRejections (internal/process/task_queues.js:84:21)

接口代码如下：

​

const express = require('express');
const app = express();

const { mongoose } = require('./db/mongoose');

// Load in the mongoose Models
const { list, task } = require('./db/models');

// Load Middleware
app.use(express.json());

// CORS Headers Middleware
app.use(function (req, res, next) {
    res.header("Access-Control-Allow-Origin", "*");
    res.header("Access-Control-Allow-Methods", "GET, POST, HEAD, OPTIONS, PUT, PATCH, DELETE");
    res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept, x-access-token, x-refresh-token, _id");

    res.header(
        'Access-Control-Expose-Headers',
        'x-access-token, x-refresh-token'
    );

    next();
});

// ROUTE HANDLERS

// LIST ROUTES

/**
 * GET /lists
 * Purpose: Get all Lists
 */
app.get('/lists', (req, res) => {
    list.find({}).then((lists) => {
        res.send(lists);
    })
})

/**
 * POST /lists
 * Purpose: Create a List
 */
app.post('/lists', (req, res) => {
    let title = req.body.title;
    let newList = new list({
        title
    });
    newList.save().then((listDoc) => {
        res.send(listDoc);
    })
});

/**
 * PATCH /lists/:id
 * Purpose: Update a List
 */
app.patch('/lists/:id', (req, res) => {
    list.findOneAndUpdate({_id: req.params.id}, {
        $set: req.body
    }).then(() => {
        res.sendStatus(200);
    })
});

/**
 * DELETE /lists/:id
 * Purpose: Delete a List
 */
app.delete('/lists/:id', (req, res) => {
    list.findByIdAndRemove({_id: req.params.id}).then((removedListDoc) => {
        res.send(removedListDoc);
    })
});

// TASK ROUTES

/**
 * GET /lists/:listId/tasks
 * Purpose: Get all Tasks in a Specific List
 */
app.get('/lists/:listId/tasks', (req, res) => {
    task.find({
        _listId: req.params.listId
    }).then((tasks) => {
        res.send(tasks);
    })
});

/**
 * GET /lists/:listId/tasks/:taskId
 * Purpose: Get one Task from a Specific List
 */
app.get('/lists/:listId/tasks/:taskId', (req, res) => {
    task.findOne({
        _taskId: req.params.taskId,
        _listId: req.params.listId
    }).then((task) => {
        res.send(task);
    })
});

/**
 * POST /lists/:listId/tasks
 * Purpose: Create a New Task in a Specified List
 */
app.post('/lists/:listId/tasks', (req, res) => {
    let newTask = new task({
        title: req.body.title,
        _listId: req.params.listId
    });
    newTask.save().then((newTaskDoc) => {
        res.send(newTaskDoc);
    })
});

/**
 * PATCH /lists/:listId/tasks/:taskId
 * Purpose: Update a Task from an Existing List
 */
app.patch('/lists/:listId/tasks/:taskId', (req, res) => {
    task.findOneAndUpdate({
        _id: req.params.taskId,
        _listId: req.params.listId
    }, {
        $set: req.body
    }).then(() => {
        res.sendStatus(200);
    })
});

/**
 * DELETE /lists/:listId/tasks/:taskId
 * Purpose: Delete a Task from an Existing List
 */
app.delete('/lists/:listId/tasks/:taskId', (req, res) => {
    task.findOneAndRemove({
        _id: req.params.taskId,
        _listId: req.params.listId
    }).then((removedTaskDoc) => {
        res.sendStatus(removedTaskDoc);
    })
});

app.listen(3000, () => {
    console.log("Server Listening at Port 3000")
})

​

express本身已经包含了正文解析器，我正在使用它。我觉得这可能是错误的原因。我不明白错误是从哪里来的。我觉得这是我的node.js应用程序接口中的某个语法错误，但我似乎找不到它。

Answer 1

我找到问题所在了。patch方法必须返回一个json对象，但我返回的是一个状态代码。将api中的代码调整为如下所示：

​

/**
 * PATCH /lists/:listId/tasks/:taskId
 * Purpose: Update a Task from an Existing List
 */
app.patch('/lists/:listId/tasks/:taskId', (req, res) => {
    task.findOneAndUpdate({
        _id: req.params.taskId,
        _listId: req.params.listId
    }, {
        $set: req.body
    }).then(() => {
        res.send({ message: "Task Updated Successfully" });
    })
});

​

将会解决这个问题。谢谢你的帮助。