modelling/lib/Persistent.ts

import { Assignable, Serializable } from './interfaces';

type PersistentTypeString = 'string'|'number'|'boolean';
type PersistentType = string|number|boolean;

export abstract class Persistent implements Assignable, Serializable {
  private _data: Record<string, PersistentType> = {};
  protected readonly properties: Record<string, PersistentTypeString> = {};

  public assign (a: Assignable): void {
    this.assign_object (a.to_object ());
  }

  public assign_to (a: Assignable): void {
    a.assign (this);
  }

  public assign_object (obj: Record<string, unknown>): void {
    for (const key of Object.keys (obj)) {
      const prop = this.properties[key];
      if (typeof prop !== 'undefined' && typeof obj[key] === prop)
        this._data[key] = obj[key] as PersistentType;
    }
  }

  public to_object (): Record<string, PersistentType> {
    return this._data;
  }

  public serialize (formatted = false): string {
    if (formatted)
      return JSON.stringify (this.to_object ());
    return JSON.stringify (this.to_object (), null, 2);
  }

  public set (key: string, value: unknown): void {
    const prop = this.properties[key];
    if (typeof prop !== 'undefined' && typeof value === prop)
      this._data[key] = value as PersistentType;
  }

  public get (key: string): PersistentType {
    return this._data[key];
  }
}