From e341d4b26f50115ccacbcde6069c19e799cbc91d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Hugo=20H=C3=A4ggmark?= <hugo.haggmark@grafana.com>
Date: Mon, 11 May 2020 10:47:05 +0200
Subject: [PATCH] Reduce Transform: sort order is preserved as entered by user
 (#24494)

---
 .../grafana-data/src/utils/Registry.test.ts   | 31 +++++++++++++++++++
 packages/grafana-data/src/utils/Registry.ts   | 14 ++++++---
 2 files changed, 41 insertions(+), 4 deletions(-)
 create mode 100644 packages/grafana-data/src/utils/Registry.test.ts

diff --git a/packages/grafana-data/src/utils/Registry.test.ts b/packages/grafana-data/src/utils/Registry.test.ts
new file mode 100644
index 00000000000..a979c2c6103
--- /dev/null
+++ b/packages/grafana-data/src/utils/Registry.test.ts
@@ -0,0 +1,31 @@
+import { Registry } from './Registry';
+import { FieldReducerInfo, fieldReducers, ReducerID } from '../transformations';
+
+describe('Registry', () => {
+  describe('selectOptions', () => {
+    describe('when called with current', () => {
+      it('then order in select.current should be same as current', () => {
+        const list = fieldReducers.list();
+        const registry = new Registry<FieldReducerInfo>(() => list);
+        const current = [ReducerID.step, ReducerID.mean, ReducerID.allIsZero, ReducerID.first, ReducerID.delta];
+        const select = registry.selectOptions(current);
+        expect(select.current).toEqual([
+          { description: 'Minimum interval between values', label: 'Step', value: 'step' },
+          { description: 'Average Value', label: 'Mean', value: 'mean' },
+          { description: 'All values are zero', label: 'All Zeros', value: 'allIsZero' },
+          { description: 'First Value', label: 'First', value: 'first' },
+          { description: 'Cumulative change in value', label: 'Delta', value: 'delta' },
+        ]);
+      });
+
+      describe('when called without current', () => {
+        it('then it should return an empty array', () => {
+          const list = fieldReducers.list();
+          const registry = new Registry<FieldReducerInfo>(() => list);
+          const select = registry.selectOptions();
+          expect(select.current).toEqual([]);
+        });
+      });
+    });
+  });
+});
diff --git a/packages/grafana-data/src/utils/Registry.ts b/packages/grafana-data/src/utils/Registry.ts
index 9ac7f0c5e4c..6dadbef2c82 100644
--- a/packages/grafana-data/src/utils/Registry.ts
+++ b/packages/grafana-data/src/utils/Registry.ts
@@ -84,10 +84,10 @@ export class Registry<T extends RegistryItem> {
       current: [],
     } as RegistrySelectInfo;
 
-    const currentIds: any = {};
+    const currentOptions: Record<string, SelectableValue<string>> = {};
     if (current) {
       for (const id of current) {
-        currentIds[id] = true;
+        currentOptions[id] = {};
       }
     }
 
@@ -106,10 +106,16 @@ export class Registry<T extends RegistryItem> {
       };
 
       select.options.push(option);
-      if (currentIds[ext.id]) {
-        select.current.push(option);
+      if (currentOptions[ext.id]) {
+        currentOptions[ext.id] = option;
       }
     }
+
+    if (current) {
+      // this makes sure we preserve the order of ids
+      select.current = Object.values(currentOptions);
+    }
+
     return select;
   }