From 861db106311ad58a4dc47a2f8ce13722c331f107 Mon Sep 17 00:00:00 2001
From: "Alex.V" <vaspiring@gmail.com>
Date: Mon, 20 Jul 2020 23:29:30 +0300
Subject: [PATCH] fix: preserve order of sorted data (#870)

---
 packages/cubejs-client-core/src/ResultSet.js  | 29 ++++++++---
 .../src/tests/ResultSet.test.js               | 52 +++++++++++++++++++
 2 files changed, 75 insertions(+), 6 deletions(-)

diff --git a/packages/cubejs-client-core/src/ResultSet.js b/packages/cubejs-client-core/src/ResultSet.js
index 5541aad366976..138d09887b260 100644
--- a/packages/cubejs-client-core/src/ResultSet.js
+++ b/packages/cubejs-client-core/src/ResultSet.js
@@ -26,6 +26,24 @@ const TIME_SERIES = {
 const DateRegex = /^\d\d\d\d-\d\d-\d\d$/;
 const LocalDateRegex = /^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}.\d{3}Z?$/;
 
+const groupByToPairs = (keyFn) => {
+  const acc = new Map();
+  
+  return (data) => {
+    data.forEach((row) => {
+      const key = keyFn(row);
+      
+      if (!acc.has(key)) {
+        acc.set(key, []);
+      }
+  
+      acc.get(key).push(row);
+    });
+    
+    return Array.from(acc.entries());
+  };
+};
+
 class ResultSet {
   constructor(loadResponse, options = {}) {
     this.loadResponse = loadResponse;
@@ -233,7 +251,7 @@ class ResultSet {
 
   pivot(pivotConfig) {
     pivotConfig = this.normalizePivotConfig(pivotConfig);
-    let groupByXAxis = groupBy(({ xValues }) => this.axisValuesString(xValues));
+    let groupByXAxis = groupByToPairs(({ xValues }) => this.axisValuesString(xValues));
 
     // eslint-disable-next-line no-unused-vars
     let measureValue = (row, measure, xValues) => row[measure];
@@ -255,8 +273,8 @@ class ResultSet {
             ({ xValues }) => moment(xValues[0]).format(moment.HTML5_FMT.DATETIME_LOCAL_MS),
             rows
           );
-          return series.map(d => ({ [d]: byXValues[d] || [{ xValues: [d], row: {} }] }))
-            .reduce((a, b) => Object.assign(a, b), {});
+          return toPairs(series.map(d => ({ [d]: byXValues[d] || [{ xValues: [d], row: {} }] }))
+            .reduce((a, b) => Object.assign(a, b), {}));
         };
 
         // eslint-disable-next-line no-unused-vars
@@ -267,8 +285,7 @@ class ResultSet {
     const xGrouped = pipe(
       map(row => this.axisValues(pivotConfig.x)(row).map(xValues => ({ xValues, row }))),
       unnest,
-      groupByXAxis,
-      toPairs
+      groupByXAxis
     )(this.timeDimensionBackwardCompatibleData());
 
     const allYValues = pipe(
@@ -284,7 +301,7 @@ class ResultSet {
     )(xGrouped);
 
     // eslint-disable-next-line no-unused-vars
-    return xGrouped.map(([xValuesString, rows]) => {
+    return xGrouped.map(([, rows]) => {
       const { xValues } = rows[0];
       const yGrouped = pipe(
         map(({ row }) => this.axisValues(pivotConfig.y)(row).map(yValues => ({ yValues, row }))),
diff --git a/packages/cubejs-client-core/src/tests/ResultSet.test.js b/packages/cubejs-client-core/src/tests/ResultSet.test.js
index 2f3f6cffeca96..2004545280011 100644
--- a/packages/cubejs-client-core/src/tests/ResultSet.test.js
+++ b/packages/cubejs-client-core/src/tests/ResultSet.test.js
@@ -912,5 +912,57 @@ describe('ResultSet', () => {
         { 'Orders.createdAt': '2020-01-10T13:50:05.000' }
       ]);
     });
+    
+    test('order is preserved', () => {
+      const resultSet = new ResultSet({
+        query: {
+          measures: ['User.total'],
+          dimensions: ['User.visits'],
+          filters: [],
+          timezone: 'UTC'
+        },
+        data: [
+          {
+            'User.total': 1,
+            'User.visits': 1
+          },
+          {
+            'User.total': 15,
+            'User.visits': 0.9
+          },
+          {
+            'User.total': 20,
+            'User.visits': 0.7
+          },
+          {
+            'User.total': 10,
+            'User.visits': 0
+          },
+        ],
+        annotation: {
+          measures: {
+            'User.total': {}
+          },
+          dimensions: {
+            'User.visits': {
+              title: 'User Visits',
+              shortTitle: 'Visits',
+              type: 'number'
+            }
+          },
+          segments: {},
+          timeDimensions: {}
+        }
+      });
+
+      expect(resultSet.pivot()).toEqual(
+        [
+          { xValues: [1], yValuesArray: [[['User.total'], 1]] },
+          { xValues: [0.9], yValuesArray: [[['User.total'], 15]] },
+          { xValues: [0.7], yValuesArray: [[['User.total'], 20]] },
+          { xValues: [0], yValuesArray: [[['User.total'], 10]] },
+        ]
+      );
+    });
   });
 });