[ENH] Add sortOrder key to sort data in descending order

src/victory-util/data.js

@@ -92,7 +92,7 @@ export default {
         );
     });
 
-    const sortedData = this.sortData(data, props.sortKey);
+    const sortedData = this.sortData(data, props.sortKey, props.sortOrder);
 
     return this.cleanData(sortedData, props);
   },
@@ -102,9 +102,10 @@ export default {
    * Sort key should correspond to the `iteratees` argument in lodash `sortBy` function.
    * @param {Array} dataset: the original dataset
    * @param {mixed} sortKey: the sort key. Type is whatever lodash permits for `sortBy`
+   * @param {String} sortOrder: the sort Order - `ascending` (default) or `descending`
    * @returns {Array} the sorted data
    */
-  sortData(dataset, sortKey) {
+  sortData(dataset, sortKey, sortOrder = "ascending") {
     if (!sortKey) {
       return dataset;
     }
@@ -114,7 +115,13 @@ export default {
       sortKey = `_${sortKey}`;
     }
 
-    return sortBy(dataset, sortKey);
+    const sortedData = sortBy(dataset, sortKey);
+
+    if (sortOrder === "descending") {
+      return sortedData.reverse();
+    }
+
+    return sortedData;
   },
 
   /**

test/client/spec/victory-util/data.spec.js

@@ -196,6 +196,23 @@ describe("helpers/data", () => {
       ]);
     });
 
+    it("sorts data according to sort key and sort order", () => {
+      const data = [
+        { x: 1, y: 1, order: 2 },
+        { x: 3, y: 3, order: 1 },
+        { x: 2, y: 2, order: 3 }
+      ];
+
+      const returnData = Data.getData({ data, sortKey: "order", sortOrder: "descending" });
+
+      expect(returnData).to.eql([
+        { _x: 2, x: 2, _y: 2, y: 2, order: 3, eventKey: 0 },
+        { _x: 1, x: 1, _y: 1, y: 1, order: 2, eventKey: 1 },
+        { _x: 3, x: 3, _y: 3, y: 3, order: 1, eventKey: 2 }
+
+      ]);
+    });
+
     // Ensures previous VictoryLine api for sortKey prop stays consistent
     it("sorts data according to evaluated sort key when sort key is x or y", () => {
       const data = [