Returns true if the ErrorResultUnion is actually an ErrorResult type. This is useful when dealing with
certain internal service method that return an ErrorResultUnion.
Example
Ts
import { isGraphQlErrorResult } from '@vendure/core';// ...const transitionResult = await this.orderService.transitionToState(ctx, order.id, newState);if (isGraphQlErrorResult(transitionResult)) { // The transition failed with an ErrorResult throw transitionResult;} else { // TypeScript will correctly infer the type of `transitionResult` to be `Order` return transitionResult;}
Signature
function isGraphQlErrorResult<T extends GraphQLErrorResult | U, U = any>(input: T): input is JustErrorResults<T>