snapshot of https://github.com/TanStack/query.git (main, 2026-09-16; blobs > 131072B omitted)

docs/framework/angular/reference/interfaces/BaseQueryNarrowing.md

@@ -0,0 +1,85 @@
+---
+id: BaseQueryNarrowing
+title: BaseQueryNarrowing
+---
+
+Defined in: [packages/angular-query-experimental/src/types.ts:83](https://github.com/TanStack/query/blob/main/packages/angular-query-experimental/src/types.ts#L83)
+
+The `isSuccess`/`isError`/`isPending` methods on a query result. Unlike `react-query`'s derived booleans,
+these are type-guard methods you call — `if (query.isSuccess())` — so that `query.data` narrows away
+`undefined` inside the branch, the same way `status` narrowing works on the plain object `react-query`
+returns.
+
+## Type Parameters
+
+### TData
+
+`TData` = `unknown`
+
+The type `data` ends up as after `select` runs.
+
+### TError
+
+`TError` = [`DefaultError`](../type-aliases/DefaultError.md)
+
+The type of errors your `queryFn` may throw.
+
+## Properties
+
+### isError()
+
+```ts
+isError: (this) => this is CreateBaseQueryResult<TData, TError, CreateStatusBasedQueryResult<"error", TData, TError>>;
+```
+
+Defined in: [packages/angular-query-experimental/src/types.ts:91](https://github.com/TanStack/query/blob/main/packages/angular-query-experimental/src/types.ts#L91)
+
+#### Parameters
+
+##### this
+
+[`CreateBaseQueryResult`](../type-aliases/CreateBaseQueryResult.md)\<`TData`, `TError`\>
+
+#### Returns
+
+`this is CreateBaseQueryResult<TData, TError, CreateStatusBasedQueryResult<"error", TData, TError>>`
+
+***
+
+### isPending()
+
+```ts
+isPending: (this) => this is CreateBaseQueryResult<TData, TError, CreateStatusBasedQueryResult<"pending", TData, TError>>;
+```
+
+Defined in: [packages/angular-query-experimental/src/types.ts:98](https://github.com/TanStack/query/blob/main/packages/angular-query-experimental/src/types.ts#L98)
+
+#### Parameters
+
+##### this
+
+[`CreateBaseQueryResult`](../type-aliases/CreateBaseQueryResult.md)\<`TData`, `TError`\>
+
+#### Returns
+
+`this is CreateBaseQueryResult<TData, TError, CreateStatusBasedQueryResult<"pending", TData, TError>>`
+
+***
+
+### isSuccess()
+
+```ts
+isSuccess: (this) => this is CreateBaseQueryResult<TData, TError, CreateStatusBasedQueryResult<"success", TData, TError>>;
+```
+
+Defined in: [packages/angular-query-experimental/src/types.ts:84](https://github.com/TanStack/query/blob/main/packages/angular-query-experimental/src/types.ts#L84)
+
+#### Parameters
+
+##### this
+
+[`CreateBaseQueryResult`](../type-aliases/CreateBaseQueryResult.md)\<`TData`, `TError`\>
+
+#### Returns
+
+`this is CreateBaseQueryResult<TData, TError, CreateStatusBasedQueryResult<"success", TData, TError>>`