无法获取所有用户的列表

Question

        getUser: (req, res, next) => {
        User.findById(req.params.id, (err, user) => {
            if (err) {
                return next(err)
            } else if (!user) {
                return res.status(404).json({ message: "User not found" })
            } else {
                return res.status(200).json({ user: user })
            }
        })
        next()
    },

    listUsers: (req, res) => {
        User.find({}, (err, users) => {
            if (err) {
                return res.status(404).json({ error: "No users found" })
            } else {
                return res.status(200).json({ users: users })
            }
        })
    }

这是路线。 router.get("/list", usersController.listUsers)

在终端中，我收到 500 错误。 它进入控制器功能并给出此错误：

错误 [ERR_HTTP_HEADERS_SENT]：发送到客户端后无法设置标头

在邮递员中，我被强制转换为 ObjectId 失败。

<h1>Cast to ObjectId failed for value &#34;list&#34; at path &#34;_id&#34; for model &#34;User&#34;</h1>
<h2></h2>
<pre>CastError: Cast to ObjectId failed for value &#34;list&#34; at path &#34;_id&#34; for model &#34;User&#34;
    at new CastError (/home/asus/Desktop/myApp/node_modules/mongoose/lib/error/cast.js:39:11)
    at ObjectId.cast (/home/asus/Desktop/myApp/node_modules/mongoose/lib/schema/objectid.js:246:11)
    at ObjectId.SchemaType.applySetters (/home/asus/Desktop/myApp/node_modules/mongoose/lib/schematype.js:975:12)
    at ObjectId.SchemaType._castForQuery (/home/asus/Desktop/myApp/node_modules/mongoose/lib/schematype.js:1389:15)
    at ObjectId.SchemaType.castForQuery (/home/asus/Desktop/myApp/node_modules/mongoose/lib/schematype.js:1379:15)
    at ObjectId.SchemaType.castForQueryWrapper (/home/asus/Desktop/myApp/node_modules/mongoose/lib/schematype.js:1358:15)
    at cast (/home/asus/Desktop/myApp/node_modules/mongoose/lib/cast.js:315:32)
    at model.Query.Query.cast (/home/asus/Desktop/myApp/node_modules/mongoose/lib/query.js:4683:12)
    at model.Query.Query._castConditions (/home/asus/Desktop/myApp/node_modules/mongoose/lib/query.js:1861:10)
    at model.Query.&lt;anonymous&gt; (/home/asus/Desktop/myApp/node_modules/mongoose/lib/query.js:2116:8)
    at model.Query._wrappedThunk [as _findOne] (/home/asus/Desktop/myApp/node_modules/mongoose/lib/helpers/query/wrapThunk.js:16:8)
    at process.nextTick (/home/asus/Desktop/myApp/node_modules/kareem/index.js:369:33)
    at process._tickCallback (internal/process/next_tick.js:61:11)</pre>