GrafanaUI: Fix Combobox throwing error with too many items (#102452)

packages/grafana-ui/src/components/Combobox/useOptions.test.ts

@@ -0,0 +1,103 @@
+import { renderHook, act, waitFor } from '@testing-library/react';
+
+import { useOptions } from './useOptions';
+
+describe('useOptions', () => {
+  it('should handle a large number of synchronous options without throwing an error', () => {
+    const largeOptions = Array.from({ length: 1_000_000 }, (_, i) => ({
+      label: `Option ${i + 1}`,
+      value: `${i + 1}`,
+    }));
+    const { result } = renderHook(() => useOptions(largeOptions, false));
+
+    act(() => {
+      result.current.updateOptions('Option 999999');
+    });
+
+    expect(result.current.options).toEqual([{ label: 'Option 999999', value: '999999' }]);
+  });
+
+  it('should return filtered options for synchronous options', () => {
+    const options = [
+      { label: 'Option 1', value: '1' },
+      { label: 'Option 2', value: '2' },
+    ];
+    const { result } = renderHook(() => useOptions(options, false));
+
+    act(() => {
+      result.current.updateOptions('Option 1');
+    });
+
+    expect(result.current.options).toEqual([{ label: 'Option 1', value: '1' }]);
+  });
+
+  it('should handle asynchronous options', async () => {
+    const asyncOptions = jest.fn().mockResolvedValue([
+      { label: 'Async Option 1', value: '1' },
+      { label: 'Async Option 2', value: '2' },
+    ]);
+    const { result } = renderHook(() => useOptions(asyncOptions, false));
+
+    act(() => {
+      result.current.updateOptions('Async');
+    });
+
+    expect(result.current.asyncLoading).toBe(true);
+
+    await waitFor(() => expect(result.current.asyncLoading).toBe(false));
+
+    expect(result.current.options).toEqual([
+      { label: 'Async Option 1', value: '1' },
+      { label: 'Async Option 2', value: '2' },
+    ]);
+  });
+
+  it('should add a custom value if enabled', () => {
+    const options = [
+      { label: 'Apple', value: 'apple' },
+      { label: 'Carrot', value: 'carrot' },
+    ];
+    const { result } = renderHook(() => useOptions(options, true));
+
+    act(() => {
+      result.current.updateOptions('car');
+    });
+
+    expect(result.current.options).toEqual([
+      { label: 'car', value: 'car', description: 'Use custom value' },
+      { label: 'Carrot', value: 'carrot' },
+    ]);
+  });
+
+  it('should not add a custom value if it already exists', () => {
+    const options = [
+      { label: 'Apple', value: 'apple' },
+      { label: 'Carrot', value: 'carrot' },
+    ];
+    const { result } = renderHook(() => useOptions(options, true));
+
+    act(() => {
+      result.current.updateOptions('carrot');
+    });
+
+    expect(result.current.options).toEqual([{ label: 'Carrot', value: 'carrot' }]);
+  });
+
+  it('should handle errors in asynchronous options', async () => {
+    jest.spyOn(console, 'error').mockImplementation();
+
+    const asyncOptions = jest.fn().mockRejectedValue(new Error('Async error'));
+    const { result } = renderHook(() => useOptions(asyncOptions, false));
+
+    act(() => {
+      result.current.updateOptions('Async');
+    });
+
+    expect(result.current.asyncLoading).toBe(true);
+
+    await waitFor(() => expect(result.current.asyncLoading).toBe(false));
+
+    expect(result.current.asyncLoading).toBe(false);
+    expect(result.current.asyncError).toBe(true);
+  });
+});

packages/grafana-ui/src/components/Combobox/useOptions.ts

@@ -1,3 +1,6 @@
+/* Spreading unbound arrays can be very slow or even crash the browser if used for arguments */
+/* eslint no-restricted-syntax: ["error", "SpreadElement"] */
+
 import { debounce } from 'lodash';
 import { useState, useCallback, useMemo } from 'react';
 
@@ -14,7 +17,7 @@ type AsyncOptions<T extends string | number> =
 const asyncNoop = () => Promise.resolve([]);
 
 /**
- * Abstracts away sync/async options for MultiCombobox (and later Combobox).
+ * Abstracts away sync/async options for combobox components.
  * It also filters options based on the user's input.
  *
  * Returns:
@@ -66,14 +69,11 @@ export function useOptions<T extends string | number>(rawOptions: AsyncOptions<T
         //we just focus on the value to check if the option already exists
         const customValueExists = opts.some((opt) => opt.value === userTypedSearch);
         if (!customValueExists) {
-          currentOptions = [
-            {
-              label: userTypedSearch,
-              value: userTypedSearch as T,
-              description: t('combobox.custom-value.description', 'Use custom value'),
-            },
-            ...currentOptions,
-          ];
+          currentOptions.unshift({
+            label: userTypedSearch,
+            value: userTypedSearch as T,
+            description: t('combobox.custom-value.description', 'Use custom value'),
+          });
         }
       }
       return currentOptions;
@@ -131,21 +131,21 @@ function sortByGroup<T extends string | number>(options: Array<ComboboxOption<T>
   let currentIndex = 0;
 
   // Reorganize options to have groups first, then undefined group
-  const reorganizeOptions = [];
+  let reorganizeOptions: Array<ComboboxOption<T>> = [];
   for (const [group, groupOptions] of groupedOptions) {
     if (!group) {
       continue;
     }
 
     groupStartIndices.set(group, currentIndex);
-    reorganizeOptions.push(...groupOptions);
+    reorganizeOptions = reorganizeOptions.concat(groupOptions);
     currentIndex += groupOptions.length;
   }
 
   const undefinedGroupOptions = groupedOptions.get(undefined);
   if (undefinedGroupOptions) {
     groupStartIndices.set('undefined', currentIndex);
-    reorganizeOptions.push(...undefinedGroupOptions);
+    reorganizeOptions = reorganizeOptions.concat(undefinedGroupOptions);
   }
 
   return {