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Express: Cannot read property 'forEach' of undefined


Express: Cannot read property 'forEach' of undefined

By : Séb
Date : October 21 2020, 08:10 AM
wish of those help I was having a problem to post on an api created with Express.js and SQL Server DB, until found the next solution: , add a null check for parameters in the function executeQuery.
code :
const executeQuery = function (res, query, parameters) {
    sql.connect(dbConfig, function (err) {
        if (err) {
            console.log(err);
            res.send(err);
        }
        else {
            var request = new sql.Request();
            if(parameters && parameters.length>0){
                parameters.forEach(function (p) {
                    request.input(p.name, p.sqltype, p.value);
                });
            }

            request.query(query, function (err, result) {
                if (err) {
                    console.log(err);
                    res.send(err);
                    sql.close();
                }
                else {
                    res.send(result.recordsets);
                    sql.close();
                }
            });
        }
    });
}


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Cannot read property 'id' of undefined. Express

Cannot read property 'id' of undefined. Express


By : David Torres
Date : March 29 2020, 07:55 AM
seems to work fine The full code is following - pretty simply i wanna add, delete or update posts - when i do one of the things by them self it works but togther it breaks , Where should it go?
code :
app.post('/', addpost);
app.post('/', editpost);
app.post('/', deletepost);
app.post('/post/add', addpost);
app.post('/post/edit', editpost);
app.post('/post/delete', deletepost);
Cannot read property 'forEach' of undefined

Cannot read property 'forEach' of undefined


By : Anonymous
Date : March 29 2020, 07:55 AM
this one helps. There is no semicolon at the end of the first line. So the two lines run together, and it is interpreted as setting the value of funcs to
code :
[][1, 2].forEach( (i) => funcs.push( () => i  ) )
[][2] // undefined
Express.js Cannot read property 'req' of undefined

Express.js Cannot read property 'req' of undefined


By : Lars Jørgensen
Date : March 29 2020, 07:55 AM
may help you . I also experienced this error, and after chewing on the error message for a bit and staring at my code for too long, It clicked.
I (and the asker above) had code that looked like this:
code :
  somethingAsync
  .then(res.send) // <-- storing send() divorced from parent object "res"
}
res = {
    send: function() { 
        console.log(this.originalMessage.req);
    },
    originalMessage: { req: "hello SO" },
};

res.send();
// # "hello SO"
const x = {};
x.send = res.send;
x.send();
// # Uncaught TypeError: Cannot read property 'req' of undefined
new Promise(_ => _())
.then(_ => console.log(this.msg.req));
// # Uncaught (in promise) TypeError: Cannot read property 'req' of undefined
handler(req, res) {
  somethingAsync
  .then(() => res.send())
   // ^ send will be called as a method of res, preserving dynamic scope
   // that is, we're storing a function that, when called, calls
   // "res.send()", instead of storing the "send" method of "res" by itself.
}
handler(req, res) {
  somethingAsync
  .then(res.send.bind(res)) // <- res is explicitly bound to the saved function as its dynamic scope
}
cannot read property 'get' undefined in express when using express router

cannot read property 'get' undefined in express when using express router


By : user3538485
Date : March 29 2020, 07:55 AM
This might help you Here is my app.js code:
code :
const { Router } = require("express");
const router = Router();

router.get('/add-product', (req, res, next) => {
  res.send('<form action="/product" method="POST"><input type="text" name="title"></input><button type="submit">Submit</form>');
});
router.get('/product', (req, res, next) => {
  console.log(req.body);
  res.redirect('/');
});

module.exports = router;
var express = require('express') - Cannot read property 'prototype' of undefined

var express = require('express') - Cannot read property 'prototype' of undefined


By : Todd Davidson
Date : March 29 2020, 07:55 AM
fixed the issue. Will look into that further I am new to Express, so forgive me if this is a simple one. I have a React project and I am trying to add Express to it. I have added a .js file that begins with the following line to import express: , You need to specify target in webpack config:
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