Merge pull request #567 from liuliangsir/master

Added getMinOrMaxValueInArrayBySomeRules utility function

snippets/reduceWhich.md

@@ -0,0 +1,16 @@
+### reduceWhich
+
+Returns the minimum/maximum value of an array, after applying the provided function to set comparing rule.
+
+Use `Array.reduce()` in combination with the `comparator` function to get the appropriate element in the array.
+You can omit the second parameter, `comparator`, to use the default one that returns the minimum element in the array.
+
+```js
+const reduceWhich = (arr, comparator = (a, b) => a - b) => arr.reduce((a, b) => comparator(a, b) >= 0 ? b : a);
+```
+
+```js
+reduceWhich([1, 3, 2]); // 1
+reduceWhich([1, 3, 2], (a, b) => b - a); // 3
+reduceWhich([{name: 'Tom', age: 12}, {name: 'Jack', age: 18}, {name: 'Lucy', age: 9}], (a, b) => a.age - b.age); // {name: "Lucy", age: 9}
+```