Add 1.8 Zero Matrix solution

Author: rroque98

JavaScript/chapter01/1.8 - Zero Matrix/rroque98_sol.js

@@ -0,0 +1,84 @@
+/*Write an algorithm such that if an element
+ in an M*N matrix is 0,it's entire row and column
+  are set to 0*/
+
+const zeroMatrix = (nestedArr) => {
+  var rowsAndColsWithZeros = checkForZeroIndex(nestedArr);
+  let rowLength = nestedArr[0].length;
+  let columnLength = nestedArr.length;
+  for (let i = 0; i < rowsAndColsWithZeros['rows'].length; i++) {
+    let rowIndex = rowsAndColsWithZeros['rows'][i];
+    for (let x = 0; x < rowLength; x++) {
+      nestedArr[rowIndex][x] = 0;
+    }
+  }
+  for (let i = 0; i < rowsAndColsWithZeros['columns'].length; i++) {
+    let colIndex = rowsAndColsWithZeros['columns'][i];
+    for (let x = 0; x < columnLength; x++) {
+      nestedArr[x][colIndex] = 0;
+    }
+  }
+  return nestedArr;
+
+  // **** Helper functions ****
+  function checkForZeroIndex(nestArr) {
+    let zeroIndices = {rows: [], columns: []};
+    for (let i = 0; i < nestArr.length; i++) {
+      for (let x = 0; x < nestArr[i].length; x++) {
+        if (nestArr[i][x] === 0) {
+          zeroIndices['rows'].push(i);
+          zeroIndices['columns'].push(x);
+        }
+      }
+    }
+    return zeroIndices;
+  }
+}
+
+// **** TESTS ****:
+
+var testArr1 = [
+  [3, 5, 6],
+  [1, 0, 2],
+  [4, 4, 5],
+  [2, 2, 2],
+]
+
+var resultArr1 = [
+  [3, 0, 6],
+  [0, 0, 0],
+  [4, 0, 5],
+  [2, 0, 2],
+]
+
+var testArr2 = [
+  [3, 5, 6],
+  [1, 0, 2],
+  [4, 4, 0],
+  [2, 0, 2],
+]
+
+var resultArr2 = [
+  [3, 0, 0],
+  [0, 0, 0],
+  [0, 0, 0],
+  [0, 0, 0],
+]
+
+var testArr3 = [
+  [3, 5, 6],
+  [0, 0, 2],
+  [4, 4, 0],
+  [2, 0, 2],
+]
+
+var resultArr3 = [
+  [0, 0, 0],
+  [0, 0, 0],
+  [0, 0, 0],
+  [0, 0, 0],
+]
+console.log(JSON.stringify(zeroMatrix(testArr1)) === JSON.stringify(resultArr1));
+console.log(JSON.stringify(zeroMatrix(testArr2)) === JSON.stringify(resultArr2));
+console.log(JSON.stringify(zeroMatrix(testArr3)) === JSON.stringify(resultArr3));
+console.log(JSON.stringify(zeroMatrix([[]])) === JSON.stringify([[]]));