Node.js Http Write after end - node.js

Question

I wrote a simple CRUD Api in node.js. I keep getting a write after end on all of my POST, PUT and DELETE functions. I have lost all sense of trying to trouble shoot this thing and was hoping for a fresh pair of eyes or some advice on trying to track it down. GET works perfectly fine and uses the same code sendJSON() in httpmgs.js.
I have scattered all kinds comments around trying to figure out where the error is happening. I didn't know if the req.on("end".... was causing an issue so I have rewritten that part to no avail.
controller.js:
switch (req.method){
case "GET":
if(req.url === "/staff"){
staff.getList(req, resp);
}
break;
case "POST":
if (req.url === "/staff/add"){
var reqBody = '';
req.on("data", function (data){
reqBody += data;
if(reqBody.length > 1e7){
msg.show413(req, resp);
}
});
req.on("end", function() {
console.log(req.data)
staff.add(req, resp, reqBody)
});
}
break;
case "PUT":
if (req.url === "/staff/update"){
var reqBody = '';
req.on("data", function (data){
reqBody += data;
if(reqBody.length > 1e7){
msg.show413(req, resp);
}
});
req.on("end", function() {
staff.update(req, resp, reqBody);
});
}
else{
msg.show404(req,resp);
}
break;
staff.js:
exports.add = function (req, resp, reqBody){
try{
if (!reqBody) throw new Error("Input not valid");
var data = JSON.parse(reqBody);
if (data){
db.executeSql("SELECT MAX(ID) AS ID FROM jarvisdb.staff",function (maxID, err){
if(err){
msg.show500(req, resp, err);
}
else{
var newID = maxID[0].ID+1
var sql = "INSERT INTO jarvisdb.staff (`ID`, `First Name`, `Last Name`) VALUES";
sql+= util.format("('%d' ,\"%s\", \"%s\")", newID, data.firstName, data.lastName);
db.executeSql(sql, (data, err)=>{
if(err){
msg.show500(req, resp, err)
}
else{
console.log('Before send')
msg.sendJSON(req,resp,data)
console.log('After send')
}
})
}
});
}
else{
throw new Error("Input not valid");
}
}
catch (ex) {
console.log('500')
msg.show500(req, resp, ex);
}
};
httpMsgs.js:
exports.sendJSON = function(req,resp,data){
if(data){
console.log('Before Write')
resp.writeHead(200, {"Content-type" : "application/json"});
console.log('Write Head')
resp.write(JSON.stringify(data));
console.log('Write body')
resp.end();
console.log('end');
}
}
Expected out:
No errors and sends back JSON
Actual results:
Listening on port 9000....
undefined
Before send
Before Write
Write Head
Write body
end
After send
events.js:174
throw er; // Unhandled 'error' event
^
Error [ERR_STREAM_WRITE_AFTER_END]: write after end
at write_ (_http_outgoing.js:572:17)
at ServerResponse.write (_http_outgoing.js:567:10)
at Object.exports.sendJSON (E:\JARVIS\API\peak-2.0\httpMsgs.js:60:14)
at db.executeSql (E:\JARVIS\API\peak-2.0\controllers\staff.js:53:33)
at Execute.conn.execute [as onResult] (E:\JARVIS\API\peak-2.0\db.js:35:9)
at process.nextTick (E:\JARVIS\API\peak-2.0\node_modules\mysql2\lib\commands\query.js:76:16)
at process._tickCallback (internal/process/next_tick.js:61:11)
Emitted 'error' event at:
at writeAfterEndNT (_http_outgoing.js:634:7)
at process._tickCallback (internal/process/next_tick.js:63:19)

Answer 1

There is no
break;
after your case. So, all cases beyond the current matched case will be executed sequentially until the end.
EDIT
Try restarting your SQL server
UPDATE
You have two options :
In your sendJSON function use:
OPTION 1 (Without Express):
resp.writeHead('Content-Type', 'application/json');
resp.end(JSON.stringify(data));
OR
OPTION 2 (With Express):
Here you don't need to specify the header type
res.json(data);