Function firstOrFail

Extension/src/Utility/System/array.ts:42–55

(iterable: Iterable<TElement> | undefined | Promise<Iterable<TElement> | undefined>, predicateOrMessage: string | Error | ((element: TElement) => true | undefined) = (e) => e as any, message?: string | Error)

export function firstOrFail<TElement>(iterable: Promise<Iterable<TElement>>, predicate: (element: TElement) => true | undefined, message: string | Error): Promise<TElement> | never;

export function firstOrFail<TElement>(iterable: Iterable<TElement> | undefined | Promise<Iterable<TElement> | undefined>, predicateOrMessage: string | Error | ((element: TElement) => true | undefined) = (e) => e as any, message?: string | Error): TElement | Promise<TElement> | never {
    let result: any;
    if (message === undefined) {
        message = predicateOrMessage as string | Error;
        predicateOrMessage = (e) => e as any;
        result = first(iterable as Iterable<TElement>, predicateOrMessage);
    } else {
        result = first(iterable as any, predicateOrMessage as any);
    }
    if (is.promise(result)) {
        return result.then(r => r !== undefined ? r : fail(message));
    }
    return result !== undefined ? result as TElement : fail(message);
}