Is it possible to initialize an entity with a config object?

Issue type:

[x] question [ ] bug report [ ] feature request [ ] documentation issue

Database system/driver:

[ ] cordova [ ] mongodb [ ] mssql [ ] mysql / mariadb [ ] oracle [ ] postgres [ ] cockroachdb [x] sqlite [ ] sqljs [ ] react-native [ ] expo

TypeORM version:

[ ] latest [ ] @next [x] 0.2.15

Steps to reproduce or a small repository showing the problem:

I modified the sample which comes with:

typeorm init --name MyProject --database sqlite

In the original setup a user is created like this:

const user = new User();
user.firstName = "Timber";
user.lastName = "Saw";
user.age = 25;

Unfortunately this doesn’t work well when you use "strict": true in your tsconfig.json because it will throw the following error:

error TS2564: Property ‘firstName’ has no initializer and is not definitely assigned in the constructor.

To avoid the above error I tried passing an object to User:

const user = new User({
  firstName: "Timber",
  lastName: "Saw",
  age: 25
});

I also updated the User.ts file:

import {Column, Entity, PrimaryGeneratedColumn} from "typeorm";

@Entity()
export class User {
  @PrimaryGeneratedColumn()
  id: number;

  @Column()
  firstName: string;

  @Column()
  lastName: string;

  @Column()
  age: number;

  constructor(params: { firstName: string, lastName: string, age: number }) {
    this.id = 0;
    this.firstName = params.firstName;
    this.lastName = params.lastName;
    this.age = params.age;
  }
}

When I now run the program, I receive the following error:

TypeError: Cannot read property ‘firstName’ of undefined at new User (D:\Temp\MyProject\src\entity\User.ts:20:29) at EntityMetadata.create (D:\Temp\MyProject\src\metadata\EntityMetadata.ts:500:19) at EntityMetadataValidator.validate (D:\Temp\MyProject\src\metadata-builder\EntityMetadataValidator.ts:111:47) at D:\Temp\MyProject\src\metadata-builder\EntityMetadataValidator.ts:44:56 at Array.forEach (<anonymous>) at EntityMetadataValidator.validateMany (D:\Temp\MyProject\src\metadata-builder\EntityMetadataValidator.ts:44:25) at Connection.buildMetadatas (D:\Temp\MyProject\src\connection\Connection.ts:508:33) at Connection.<anonymous> (D:\Temp\MyProject\src\connection\Connection.ts:189:18) at step (D:\Temp\MyProject\node_modules\tslib\tslib.js:133:27) at Object.next (D:\Temp\MyProject\node_modules\tslib\tslib.js:114:57)

How come that firstName is undefined? In my code I never call new User without a configuration object.

Is TypeORM doing some magic in the background and calls new User() (without giving it a parameter)?

[abingoal]

When you use "strict": true in your tsconfig.json, you must modify your entity like this:

@Entity()
export class User {
  @PrimaryGeneratedColumn()
  id!: number;

  @Column()
  firstName!: string;

  @Column()
  lastName!: string;

  @Column()
  age!: number;
}

just add a bang sign (!).

[bennycode]

@vlapo I tested with typeorm v0.3.0-alpha.24 and it works now. Thank you very much! 🥳

Here is my full test code for people finding this issue:

initDatabase.ts

import 'reflect-metadata';
import {Connection, createConnection} from 'typeorm';
import {SqliteConnectionOptions} from 'typeorm/driver/sqlite/SqliteConnectionOptions';
import {PostgresConnectionOptions} from 'typeorm/driver/postgres/PostgresConnectionOptions';
import {User} from './entity/User';

export default function initDatabase(): Promise<Connection> {
  const localhost: SqliteConnectionOptions = {
    database: 'test.db3',
    type: 'sqlite'
  };

  const production: PostgresConnectionOptions = {
    type: 'postgres',
    url: process.env.DATABASE_URL
  };

  const connectionOptions = (process.env.NODE_ENV === 'production') ? production : localhost;

  Object.assign(connectionOptions, {
    entities: [
      User
    ],
    logging: false,
    migrations: [
      'src/migration/**/*.ts'
    ],
    subscribers: [
      'src/subscriber/**/*.ts'
    ],
    synchronize: true,
  });

  return createConnection(connectionOptions);
};

User.ts

import {BaseEntity, Column, Entity, PrimaryGeneratedColumn} from "typeorm";

@Entity()
export class User extends BaseEntity {
  @PrimaryGeneratedColumn()
  id: number;

  @Column()
  firstName: string;

  @Column()
  lastName: string;

  @Column()
  age: number;

  constructor(params: { firstName: string, lastName: string, age: number }) {
    super();
    this.id = 0;
    this.firstName = params.firstName;
    this.lastName = params.lastName;
    this.age = params.age;
  }
}

index.ts

import initDatabase from "./initDatabase";
import {User} from "./entity/User";

(async () => {
  await initDatabase();
  const user = new User({
    firstName: "Timber",
    lastName: "Saw",
    age: 25
  });
  await user.save();
})();