Question

我开发了一个Angular4基本CRUD应用程序，它与nodejs后端API交互，后端API呈现JSON数组的数据。但是在使用.push（）方法向JSON数组添加对象时，它会将最后一个对象替换为要添加的新对象，而不是将其推送到数组。

以下是员工的定义：

export interface Employee {
id:number,
name:string,
review:string[],
peers:string[]
}

服务方法使HTTP调用如下：

addEmployee(addedEmployee:Employee):Observable<Response>
{
return 
this._http.post("http://localhost:3001/add",addedEmployee)
.pipe(catchError(this.handleError));
}

将一个Employee对象添加到JSON对象数组的后端API代码如下：

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);
})

后端JSON对象数组的before，intermediate和after结构如下：

在：

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"]
}
];

中间体：

let addedEmployee:Employee = {
  id: 4,
  name: "Trudy",
    review:["Lazy"],
    peers: ["Matt"]
  };

决赛：

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

这很奇怪。这可能不是最佳解决方案，但请尝试使用.concat（）方法：

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);
})

为什么.push（）替换JSON数组的最后一个对象？

1 个答案: