How to send a number to node.js from Angular - html

Question

I am working on a full stack development using Angular, Node and mySQL. I have to send an index number of a list that the user clicks on an HTML, to a node.js where then, I will have to delete that index row from mySQL. However, I am getting an unusual error. This is my code:
HTML
<tbody *ngFor = "let db of dbData" >
<tr>
<td>{{+db.idoffice + +1}}</td>
<td>{{db.ProjectName}}</td>
<td>{{db.FiscalYear}}</td>
<td>{{db.TaskDescription}}</td>
<td>{{db.ConcernedDepartment}}</td>
<td>{{db.ActivityType}}</td>
<td>{{db.Quarter}}</td>
<td>{{db.kra}}</td>
<td>{{db.CurrentStatus}}</td>
<td>{{db.ResourceName}}</td>
<td>{{db.Notes}}</td>
<td><button class = "btn btn-success nc-icon nc-refresh-69" name="button"></button></td>
<td><button class = "btn btn-danger nc-icon nc-simple-delete" name="button" (click) =
"onDeletePosts(db.idoffice)"></button></td>
</tr>
</tbody>
Angular
private onDeletePosts(delData)
{
this.http.delete('http://localhost:3000/del', delData)
.subscribe(responseData => {
console.log(responseData);
});
}
Node.js
router.delete("/del", (req, res) => {
var del = req.body.delData;
console.log(del);
mysqlConnection.query("DELETE FROM office WHERE idOffice == ?", del , (err, results) => {
if(!err)
{
res.send(results);
}
else
{
console.log("Error occured while deleting" + err.message);
}
})
})
This is the error that I am getting:
undefined //somehow the data from angular to node isn't being received
Error occured while deletingER_PARSE_ERROR: You have an error in your SQL syntax; check the manual
that corresponds to your MySQL server version for the right syntax to use near '== ?' at line 1

Answer 1

Angular HttpClient's delete method does not take a body in it's argument. Instead you could send the ID as an URL query parameter.
Angular
import { HttpClient, HttpParams } from '#angular/common/http';
private onDeletePosts (delData: any) {
const params = new HttpParams().set('id', delData);
this.http.delete('http://localhost:3000/del', { params }).subscribe({
next: responseData => { console.log(responseData); },
error: error => { console.log(error); }
});
}
Node.js
router.delete("/del", (req, res) => {
var id = req.query.id;
console.log(id);
mysqlConnection.query("DELETE FROM office WHERE idOffice == ?", id, (err, results) => {
if (!err) {
res.send(results);
} else {
console.log("Error occured while deleting" + err.message);
}
})
})

Answer 2

It says there's something wrong with the query syntax.
The comparison operator you used is "==". There is no double equal in MySQL, so it's supposed to be "="

Answer 3

Angular
private onDeletePosts(del_id)
{
this.http.delete(`http://localhost:3000/del/${del_id}`)
.subscribe(responseData => {
console.log(responseData);
});
}
node.js
router.delete("/del/:del", (req, res) => {
const { del } = req.params;
console.log(del);
mysqlConnection.query("DELETE FROM office WHERE idOffice == ?", del, (err, results) => {
if (!err) {
res.send(results);
}
else {
console.log("Error occured while deleting" + err.message);
}
})
})