Check if there is no id in database node.js-CodePudding

so bassically, i am creating a router to update data in database, I started by checking the id in database using if function, at first it works when there is no such id I put in the path, but its come out with this error

BError [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client at ServerResponse.setHeader (_http_outgoing.js:558:11) at ServerResponse.header (C:\Users\jansen stanlie\Desktop\simple-app\node_modules\express\lib\response.js:794:10) at ServerResponse.send (C:\Users\jansen stanlie\Desktop\simple-app\node_modules\express\lib\response.js:174:12) at ServerResponse.json (C:\Users\jansen stanlie\Desktop\simple-app\node_modules\express\lib\response.js:278:15) at C:\Users\jansen stanlie\Desktop\simple-app\controllers\todo.controller.js:79:21 at Array.forEach () at C:\Users\jansen stanlie\Desktop\simple-app\controllers\todo.controller.js:60:9 at processTicksAndRejections (internal/process/task_queues.js:93:5) at async putToDo (C:\Users\jansen stanlie\Desktop\simple-app\controllers\todo.controller.js:54:2) { code: 'ERR_HTTP_HEADERS_SENT' } (node:12008) UnhandledPromiseRejectionWarning: Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client at ServerResponse.setHeader (_http_outgoing.js:558:11) at ServerResponse.header (C:\Users\jansen stanlie\Desktop\simple-app\node_modules\express\lib\response.js:794:10) at ServerResponse.send (C:\Users\jansen stanlie\Desktop\simple-app\node_modules\express\lib\response.js:174:12) at ServerResponse.json (C:\Users\jansen stanlie\Desktop\simple-app\node_modules\express\lib\response.js:278:15) at C:\Users\jansen stanlie\Desktop\simple-app\controllers\todo.controller.js:86:20 at processTicksAndRejections (internal/process/task_queues.js:93:5) at async putToDo (C:\Users\jansen stanlie\Desktop\simple-app\controllers\todo.controller.js:54:2) (Use node --trace-warnings ... to show where the warning was created) (node:12008) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag --unhandled-rejections=strict (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1) (node:12008) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

and after that I cannot update any data even though there is in the database

here is my code

const putToDo = async (req, res) => {
const body = req.body;
let id = req.params.id;
console.log(id);
let data = [];
let updatedData = [];
await db
    .query("select * from suppliers")
    .then((results) => {
        data = results.rows;
    })
    .then(() => {
        data.forEach((datas) => {
            if (datas.id == id) {
                db.query(
                    `UPDATE suppliers
                SET Name = '${body.name}'
                WHERE id = ${id};`
                )
                    .then(() => {
                        db.query("select * from suppliers").then((updated) => {
                            updatedData = updated;
                            console.log(updatedData);
                        });
                    })
                    .then(() => {
                        res.status(200).json({
                            message: "Data Successfully Updated",
                        });
                    });
            }
            res.status(500).json({
                message: "No data in database",
            });
        });
    })
    .catch((e) => {
        console.log(e);
        res.status(500).json({
            message: "INTERNAL SERVER ERROR",
        });
    });};

where did I do wrong here...?

CodePudding user response：

The error says you are trying to set headers after already sending a response

Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client at

That is because your res.status(500)

res.status(500).json({message: "No data in database"});

Runs after the res.status(200).json()

res.status(200).json({ message: "Data Successfully Updated"})

Try adding an else to your condition so only 1 or the other will execute.

if (datas.id == id) {
                db.query(
                    `UPDATE suppliers
                SET Name = '${body.name}'
                WHERE id = ${id};`
                )
                    .then(() => {
                        db.query("select * from suppliers").then((updated) => {
                            updatedData = updated;
                            console.log(updatedData);
                        });
                    })
                    .then(() => {
                        res.status(200).json({
                            message: "Data Successfully Updated",
                        });
                    });
} else {
       res.status(500).json({
          message: "No data in database",
       });
}

Additionally, you are using res.status().json() multiple times within a loop, but should likely only be sending 1 response back that includes all the data instead of a response for every item in the looped data.

CodePudding user response：

Try this

res.status(200).json()