// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
// This module is browser compatible.

/**
 * Applies the given selector to elements in the given array until a value is
 * produced that is neither `null` nor `undefined` and returns that value.
 * Returns `undefined` if no such value is produced.
 *
 * @example
 * ```ts
 * import { firstNotNullishOf } from "@std/collections/first_not_nullish_of";
 * import { assertEquals } from "@std/assert/assert_equals";
 *
 * const tables = [
 *   { number: 11, order: null },
 *   { number: 12, order: "Soup" },
 *   { number: 13, order: "Salad" },
 * ];
 * const nextOrder = firstNotNullishOf(tables, (it) => it.order);
 *
 * assertEquals(nextOrder, "Soup");
 * ```
 */
export function firstNotNullishOf<T, O>(
  array: Iterable<T>,
  selector: (item: T) => O | undefined | null,
): NonNullable<O> | undefined {
  for (const current of array) {
    const selected = selector(current);

    if (selected !== null && selected !== undefined) {
      return selected as NonNullable<O>;
    }
  }

  return undefined;
}