docs(util): added jsdoc annotations for ArrayHelpers.js

Author: taranek

lib/util/ArrayHelpers.js

@@ -5,6 +5,14 @@
 
 "use strict";
 
+/**
+ * Compare two arrays or strings by performing strict equality check for each value.
+ * @template T [T=any]
+ * @param {ArrayLike<T>} a Array of values to be compared
+ * @param {ArrayLike<T>} b Array of values to be compared
+ * @returns {boolean} returns true if all the elements of passed arrays are strictly equal.
+ */
+
 exports.equals = (a, b) => {
 	if (a.length !== b.length) return false;
 	for (let i = 0; i < a.length; i++) {
@@ -14,13 +22,19 @@ exports.equals = (a, b) => {
 };
 
 /**
- *
- * @param {Array} arr Array of values to be partitioned
- * @param {(value: any) => boolean} fn Partition function which partitions based on truthiness of result.
- * @returns {[Array, Array]} returns the values of `arr` partitioned into two new arrays based on fn predicate.
+ * Partition an array by calling a predicate function on each value.
+ * @template T [T=any]
+ * @param {Array<T>} arr Array of values to be partitioned
+ * @param {(value: T) => boolean} fn Partition function which partitions based on truthiness of result.
+ * @returns {[Array<T>, Array<T>]} returns the values of `arr` partitioned into two new arrays based on fn predicate.
  */
 exports.groupBy = (arr = [], fn) => {
 	return arr.reduce(
+		/**
+		 * @param {[Array<T>, Array<T>]} groups An accumulator storing already partitioned values returned from previous call.
+		 * @param {T} value The value of the current element
+		 * @returns {[Array<T>, Array<T>]} returns an array of partitioned groups accumulator resulting from calling a predicate on the current value.
+		 */
 		(groups, value) => {
 			groups[fn(value) ? 0 : 1].push(value);
 			return groups;