Just another update

Task/Top-rank-per-group/JavaScript/top-rank-per-group-1.js

@@ -26,7 +26,7 @@ function top_rank(n) {
     }
 }
 
-// group by dept, and sort by balary
+// group by dept, and sort by salary
 function group_by_dept(data) {
     var by_dept = {};
     for (var idx in data)  {

Task/Top-rank-per-group/JavaScript/top-rank-per-group-2.js

@@ -0,0 +1,31 @@
+var collectDept = function (arrOfObj) {
+  var collect = arrOfObj.reduce(function (rtnObj, obj) {
+    if (rtnObj[obj.dept] === undefined) {
+      rtnObj[obj.dept] = [];
+    }
+    rtnObj[obj.dept].push(obj);
+    return rtnObj;
+  }, {});
+
+  return Object.keys(collect).map(function (key) {
+    return collect[key];
+  });
+};
+
+var sortSalary = function (arrOfSalaryArrs) {
+  return arrOfSalaryArrs.map(function (item) {
+    return item.sort(function (a, b) {
+      if (a.salary > b.salary) { return -1; }
+      if (a.salary < b.salary) { return 1; }
+      return 0;
+    });
+  });
+};
+
+var getNTopSalariesByDept = function (n, data) {
+  if (n < 0) { return; }
+
+  return sortSalary(collectDept(data)).map(function (list) {
+    return list.slice(0,n);
+  });
+};