Chore: Stricter typing in type guards (#77809)

* Stricter typing in type guards

* create utility isObject fn

* better isAlertStateWithReason

* better name

* restore "data !== undefined"

packages/grafana-data/src/types/data.test.ts

@@ -0,0 +1,61 @@
+import { isObject, isTruthy } from './data';
+
+describe('isObject', () => {
+  it.each([
+    // [value, expected]
+
+    // These are objects
+    [{}, true],
+    [[], true],
+    [{ a: 1 }, true],
+    [new Date(), true],
+    [new Error(), true],
+
+    // These are not!
+    [parseInt('blabla', 10), false], // NaN
+    [null, false],
+    [undefined, false],
+    [-Infinity, false],
+    [-42, false],
+    [0, false],
+    [-0, false],
+    [42, false],
+    [Infinity, false],
+    ['foo', false],
+    [true, false],
+    [Symbol(), false],
+    [() => {}, false],
+  ])('should return %p for %p', (input, expected) => {
+    expect(isObject(input)).toBe(expected);
+  });
+});
+
+describe('isTruthy', () => {
+  it.each([
+    // [value, expected]
+
+    // These are truthy
+    [true, true],
+    [-Infinity, true],
+    [-42, true],
+    [42, true],
+    [Infinity, true],
+    ['foo', true],
+    [{}, true],
+    [[], true],
+    [() => {}, true],
+    [Symbol(), true],
+    [new Date(), true],
+
+    // These are falsy
+    [false, false],
+    [0, false],
+    [-0, false],
+    ['', false],
+    [null, false],
+    [undefined, false],
+    [parseInt('blabla', 10), false], // NaN
+  ])('should return %p for %p', (input, expected) => {
+    expect(isTruthy(input)).toBe(expected);
+  });
+});

packages/grafana-data/src/types/data.ts

@@ -213,3 +213,27 @@ export interface DataConfigSource {
 
 type Truthy<T> = T extends false | '' | 0 | null | undefined ? never : T;
 export const isTruthy = <T>(value: T): value is Truthy<T> => Boolean(value);
+
+/**
+ * Serves no runtime purpose - only used to make typescript check a value has been correctly
+ * narrowed to an object
+ */
+function identityObject(value: object): object {
+  return value;
+}
+
+/**
+ * Utility type predicate to check if a value is typeof object, but excludes "null".
+ *
+ * We normally discourage the use of type predicates in favor of just inline typescript narrowing,
+ * but this is a special case to handle null annoyingly being typeof object
+ */
+export function isObject(value: unknown): value is object {
+  if (typeof value === 'object' && value !== null) {
+    identityObject(value);
+
+    return true;
+  }
+
+  return false;
+}

packages/grafana-data/src/utils/OptionsUIBuilders.ts

@@ -16,6 +16,7 @@ import {
   StandardEditorContext,
 } from '../field';
 import { PanelOptionsSupplier } from '../panel/PanelPlugin';
+import { isObject } from '../types';
 import { OptionsEditorItem, OptionsUIRegistryBuilder } from '../types/OptionsUIRegistryBuilder';
 import { FieldConfigEditorProps, FieldConfigPropertyItem, FieldConfigEditorConfig } from '../types/fieldOverrides';
 import { PanelOptionsEditorConfig, PanelOptionsEditorItem } from '../types/panel';
@@ -204,8 +205,8 @@ export class NestedPanelOptionsBuilder<TSub = any> implements OptionsEditorItem<
   };
 }
 
-export function isNestedPanelOptions(item: any): item is NestedPanelOptionsBuilder {
-  return item.id === 'nested-panel-options';
+export function isNestedPanelOptions(item: unknown): item is NestedPanelOptionsBuilder {
+  return isObject(item) && 'id' in item && item.id === 'nested-panel-options';
 }
 
 /**