modelling/lib/Persistent.ts

import { copy_object } from '@sapphirecode/utilities';
import { Assignable, Serializable } from './interfaces';

type PersistentTypeString = 'string'|'number'|'boolean'|'array';
type PersistentPrimitive = string|number|boolean;
type PersistentType = PersistentPrimitive|PersistentPrimitive[];

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 copy_object (this._data);
  }

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

  private check_type (value: unknown, prop: PersistentTypeString): boolean {
    if (typeof prop === 'undefined')
      return false;
    if (prop === 'array')
      return Array.isArray (value);

    return typeof value === prop;
  }

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

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