Source: collections/EqualityComparer.js

  1. /**
  2.  * A base-class for equality comparers.
  3.  * 
  4.  * @template T
  5.  * @author Sebastian Hönel <development@hoenel.net>
  6.  */
  7. class EqualityComparer {
  8. 	/**
  9. 	 * Returns an instance of the DefaultEqualityComparer<T> that uses the identity-operator.
  10. 	 * 
  11. 	 * @template TDefault
  12. 	 * @type {DefaultEqualityComparer<TDefault>}
  13. 	 */
  14. 	static get default() {
  15. 		return new DefaultEqualityComparer();
  16. 	};
  18. 	/**
  19. 	 * @param {T} x
  20. 	 * @param {T} y
  21. 	 * @throws {Error} This is an abstract method.
  22. 	 * @returns {Boolean} True, iff the two items x and y are considered
  23. 	 * to be equal.
  24. 	 */
  25. 	equals(x, y) {
  26. 		throw new Error('Abstract method');
  27. 	};
  28. };
  31. /**
  32.  * The DefaultEqualityComparer uses the identity-operator to compare equality.
  33.  * 
  34.  * @template T
  35.  * @author Sebastian Hönel <development@hoenel.net>
  36.  */
  37. class DefaultEqualityComparer extends EqualityComparer {
  38. 	/**
  39. 	 * Checks equality using the identity-operator (===).
  40. 	 * 
  41. 	 * @param {T} x 
  42. 	 * @param {T} y 
  43. 	 * @returns {Boolean} True, iff the two items are identical.
  44. 	 */
  45. 	equals(x, y) {
  46. 		return x === y;
  47. 	};
  48. };
  51. module.exports = Object.freeze({
  52. 	EqualityComparer,
  53. 	DefaultEqualityComparer
  54. });