upstream-tanstack-query/docs/framework/angular/reference/interfaces/BaseQueryNarrowing.md

id, title

id	title
BaseQueryNarrowing	BaseQueryNarrowing

Defined in: packages/angular-query-experimental/src/types.ts:83

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

The type of errors your queryFn may throw.

Properties

isError()

isError: (this) => this is CreateBaseQueryResult<TData, TError, CreateStatusBasedQueryResult<"error", TData, TError>>;

Defined in: packages/angular-query-experimental/src/types.ts:91

Parameters

this

CreateBaseQueryResult<TData, TError>

Returns

this is CreateBaseQueryResult<TData, TError, CreateStatusBasedQueryResult<"error", TData, TError>>

---

isPending()

isPending: (this) => this is CreateBaseQueryResult<TData, TError, CreateStatusBasedQueryResult<"pending", TData, TError>>;

Defined in: packages/angular-query-experimental/src/types.ts:98

Parameters

this

CreateBaseQueryResult<TData, TError>

Returns

this is CreateBaseQueryResult<TData, TError, CreateStatusBasedQueryResult<"pending", TData, TError>>

---

isSuccess()

isSuccess: (this) => this is CreateBaseQueryResult<TData, TError, CreateStatusBasedQueryResult<"success", TData, TError>>;

Defined in: packages/angular-query-experimental/src/types.ts:84

Parameters

this

CreateBaseQueryResult<TData, TError>

Returns

this is CreateBaseQueryResult<TData, TError, CreateStatusBasedQueryResult<"success", TData, TError>>