How to parse a JSON object to a TypeScript Object

Question

I am currently trying to convert my received JSON Object into a TypeScript class with the same attributes and I cannot get it to work. What am I doing wrong?

Answer 1

i like to use a littly tiny library called class-transformer.

it can handle nested-objects, map strings to date-objects and handle different json-property-names a lot more.

Maybe worth a look.

import { Type, plainToClass, Expose } from "class-transformer";
import 'reflect-metadata';

export class Employee{
    @Expose({ name: "uid" })
    id: number;

    firstname: string;
    lastname: string;
    birthdate: Date;
    maxWorkHours: number;
    department: string;

    @Type(() => Permission)
    permissions: Permission[] = [];
    typeOfEmployee: string;
    note: string;

    @Type(() => Date)
    lastUpdate: Date;
}

export class Permission {
  type : string;
}

let json:string = {
    "uid": 123,
    "department": "",
    "typeOfEmployee": "",
    "firstname": "",
    "lastname": "",
    "birthdate": "",
    "maxWorkHours": 1,
    "username": "",
    "permissions": [
      {'type' : 'read'},
      {'type' : 'write'}
    ],
    "lastUpdate": "2020-05-08"
}

console.log(plainToClass(Employee, json));

```