Add comparator annotations.

Author: trekhleb

src/utils/comparator/Comparator.js

@@ -1,12 +1,14 @@
 export default class Comparator {
   /**
-   * @param {function(a: *, b: *)} [compareFunction]
+   * @param {function(a: *, b: *)} [compareFunction] - It may be custom compare function that, let's
+   * say may compare custom objects together.
    */
   constructor(compareFunction) {
     this.compare = compareFunction || Comparator.defaultCompareFunction;
   }
 
   /**
+   * Default comparison function. It just assumes that "a" and "b" are strings or numbers.
    * @param {(string|number)} a
    * @param {(string|number)} b
    * @returns {number}
@@ -19,26 +21,59 @@ export default class Comparator {
     return a < b ? -1 : 1;
   }
 
+  /**
+   * Checks if two variables are equal.
+   * @param {*} a
+   * @param {*} b
+   * @return {boolean}
+   */
   equal(a, b) {
     return this.compare(a, b) === 0;
   }
 
+  /**
+   * Checks if variable "a" is less than "b".
+   * @param {*} a
+   * @param {*} b
+   * @return {boolean}
+   */
   lessThan(a, b) {
     return this.compare(a, b) < 0;
   }
 
+  /**
+   * Checks if variable "a" is greater than "b".
+   * @param {*} a
+   * @param {*} b
+   * @return {boolean}
+   */
   greaterThan(a, b) {
     return this.compare(a, b) > 0;
   }
 
+  /**
+   * Checks if variable "a" is less than or equal to "b".
+   * @param {*} a
+   * @param {*} b
+   * @return {boolean}
+   */
   lessThanOrEqual(a, b) {
     return this.lessThan(a, b) || this.equal(a, b);
   }
 
+  /**
+   * Checks if variable "a" is greater than or equal to "b".
+   * @param {*} a
+   * @param {*} b
+   * @return {boolean}
+   */
   greaterThanOrEqual(a, b) {
     return this.greaterThan(a, b) || this.equal(a, b);
   }
 
+  /**
+   * Reverses the comparison order.
+   */
   reverse() {
     const compareOriginal = this.compare;
     this.compare = (a, b) => compareOriginal(b, a);