ValueObject model

value-object.model.ts

import type { ObjectPlain } from '@flex-development/tutils'
import isNIL from '@flex-development/tutils/guards/is-nil.guard'
import { shallowEqual } from 'shallow-equal-object'

/**
 * @file Models - ValueObject
 * @module models/ValueObject
 */

/**
 * Base value object class.
 *
 * A value object is an object that can have its equality determined through
 * its structrual property, rather than its identity (like an entity).
 *
 * @see https://khalilstemmler.com/articles/typescript-value-object
 *
 * @template T - Value object props
 */
export default class ValueObject<T extends ObjectPlain = ObjectPlain> {
  constructor(readonly props: T) {
    this.props = Object.freeze(props)
  }

  /**
   * Determines if the current value object is equal to `obj`.
   *
   * @template T1 - Value object props for {@link obj}
   *
   * @param {ValueObject<any>} obj - Value object to check
   * @return {boolean} `true` if equal, `false`, otherwise
   */
  equals<T1 extends ObjectPlain = ObjectPlain>(obj: ValueObject<T1>): boolean {
    if (isNIL(obj) || obj.props === undefined) return false
    return shallowEqual(this.props, obj.props)
  }
}