如何从 Json 数据创建 TypeScript 类？

Question

I'm using Angular to call an external API. Json data is in format like:

[
      {
        "AccessGroupsIdList": [],
        "FirstName": "Greg",
        "LastName": "Tipton",
        "LocationIdList": [],
        "PermissionProfile": {
          "Name": "Agent",
          "PermissionProfileId": {
            "ID": "xy678219-bd7c-103d-b56b-1f1234a85990"
          },
          "Type": 3
        },
        "ManagerName": "Gilchrist, George",
        "Status": true,
        "UserGroupID": {
          "ID": "00000000-0000-0000-0000-000000000000"
        },
        "UserGroupName": "ROOT",
        "UserId": {
          "ID": "4445cc66-819a-4da0-8fbf-d0bb8ce65941"
        }
      }
    ]

How do I create a class in typescript to read it since json data is nested?

export class Employees
{
AccessGroupsIdList: string[];
FirstName: string;
LastName: string;
LocationIdList : number[];
PermissionProfile ??
ManagerName: string;
Status: boolean;
UserGroupID ??
UserGroupName : string;
UserId ??
}

Please guide if the PermissionProfile, PermissionProfile will be separate nested classes? How do I declare those?

Answer 1

Try declaring the Typescript class structures as follows:

export class Employees
{
    AccessGroupsIdList: string[];
    FirstName: string;
    LastName: string;
    LocationIdList : number[];
    PermissionProfile: PermissionProfile;
    ManagerName: string;
    Status: boolean;
    UserGroupId: UserGroupID;
    UserGroupName : string;
    UserId: UserID;
}

export class PermissionProfile 
{
    name: string;
    permissionProfileId: PermissionProfileID;
    type: string;
}

export class PermissionProfileID
{
    id: string;
}
 
export class UserGroupID
{
    id: string;
}

export class UserID
{
    id: string;
}

I would suggest to name the property names consistently with an Id (eg with UserGroupId ). The name and type class property names are valid in TypeScript (unlike with the C# syntax).

Answer 2

To extend Andrew Halil's answer, I would use interfaces instead of classes in your definitions, since there do not appear to be any class methods involved; you are just describing the shape of a JSON object returned from a server

export interface Employee
{
    AccessGroupsIdList: string[];
    FirstName: string;
    LastName: string;
    LocationIdList : number[];
    PermissionProfile: PermissionProfile;
    ManagerName: string;
    Status: boolean;
    UserGroupId: ID;
    UserGroupName : string;
    UserId: ID;
}

export interface PermissionProfile 
{
    name: string;
    permissionProfileId: ID;
    type: string;
}

export interface ID
{
    id: string;
}
 

Now as for an implementation, I don't use Angular all that much but you would do something like this to get the items typed

async function listEmployees(): Promise<Employee[]> {
// Make a fetch call to the API endpoint
   const data = await fetch('https://some-api-endpoint.web/employees')
      // if the response comes back ok, return the JSON-ified response.
      .then(res => {
          if(res.ok) return res.json()
          return [];
      });
    // Instruct typescript that "data" is to be treated as an array of Employee elements.
    return data as Employee[]
}