Returns array with negatives from nested arrays

14th exercise - #1351
https://leetcode.com/problems/count-negative-numbers-in-a-sorted-matrix/submissions/

numberOfNegative.js

@@ -0,0 +1,42 @@
+/*
+Given a m * n matrix grid which is sorted in non-increasing order both row-wise and column-wise. 
+
+Return the number of negative numbers in grid.
+
+ 
+
+Example 1:
+
+Input: grid = [[4,3,2,-1],[3,2,1,-1],[1,1,-1,-2],[-1,-1,-2,-3]]
+Output: 8
+Explanation: There are 8 negatives number in the matrix.
+Example 2:
+
+Input: grid = [[3,2],[1,0]]
+Output: 0
+Example 3:
+
+Input: grid = [[1,-1],[-1,-1]]
+Output: 3
+Example 4:
+
+Input: grid = [[-1]]
+Output: 1
+ 
+
+Constraints:
+
+m == grid.length
+n == grid[i].length
+1 <= m, n <= 100
+-100 <= grid[i][j] <= 100
+*/
+
+//Answer//
+/**
+ * @param {number[][]} grid
+ * @return {number}
+ */
+var countNegatives = function(grid) {
+return grid.map(x=>x.filter(y=>y<0).length).reduce((a, b) => a + b) 
+};