Why .push() replacing the last object of JSON array? - json

Question

I have developed an Angular4 basic CRUD application that interacts with a nodejs backend API that renders data of a JSON array. But on adding an object to the JSON array using .push() method it replaces the last object with the new to be added object instead of pushing it to the array.
The following is the definition of Employee :
export interface Employee {
id:number,
name:string,
review:string[],
peers:string[]
}
The service method makes the HTTP call is following:
addEmployee(addedEmployee:Employee):Observable<Response>
{
return
this._http.post("http://localhost:3001/add",addedEmployee)
.pipe(catchError(this.handleError));
}
The backend API code that adds an Employee object to JSON object array is following:
app.post('/add',function(req,res){
var addedEmployee={};
addedEmployee.id=req.body.id;
addedEmployee.name=req.body.name;
addedEmployee.review=req.body.review;
addedEmployee.peers=req.body.peers;
employees.push(addedEmployee);
console.log('added');
res.json(employees);
})
The before, intermediate and after structures of the backend JSON object array are following:
Before:
employees = [
{
id: 1,
name: "John Doe",
review: ["Hardworking"],
peers: ["admin", "Matt"]
},
{
id: 2,
name: "Matt Hofner",
review: ["Hardworking"],
peers: ["admin"]
},
{
id: 3,
name: "Judy Ruth",
review: ["Focused"],
peers: ["admin", "Matt"]
}
];
Intermediate:
let addedEmployee:Employee = {
id: 4,
name: "Trudy",
review:["Lazy"],
peers: ["Matt"]
};
Final :
employees = [
{
id: 1,
name: "John Doe",
review: ["Hardworking"],
peers: ["admin", "Matt"]
},
{
id: 2,
name: "Matt Hofner",
review: ["Hardworking"],
peers: ["admin"]
},
{
id: 4,
name: "Trudy",
review: ["Lazy"],
peers: ["Matt"]
}
];

Answer 1

That's odd. This might not be the best solution but try the .concat() method :
app.post('/add',function(req,res){
var addedEmployee={};
var singleEmployeeArray = [];
addedEmployee.id=req.body.id;
addedEmployee.name=req.body.name;
addedEmployee.review=req.body.review;
addedEmployee.peers=req.body.peers;
singleEmployeeArray.push(addedEmployee);
employees.concat(singleNewEmployeeArray);
console.log('added');
res.json(employees);
})