firstNotNullishOf

function

function firstNotNullishOf<T, O>(array: Iterable<T>, selector: (item: T, index: number) => O | undefined | null): NonNullable<O> | undefined

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.

array: Iterable<T>

The array to select a value from.

selector: (item: T, index: number) => O | undefined | null

The function to extract a value from an element. The function receives the element and its index.

Returns

The first non-null and non-undefined value produced by the selector function, or undefined if no such value is produced.

import { firstNotNullishOf } from "@ende/collections/first-not-nullish-of";
import { assertEquals } from "@ende/assert";

const tables = [
  { number: 11, order: null },
  { number: 12, order: "Soup" },
  { number: 13, order: "Salad" },
];

const nextOrder = firstNotNullishOf(tables, (table) => table.order);

assertEquals(nextOrder, "Soup");

import { firstNotNullishOf } from "@ende/collections/first-not-nullish-of";
import { assertEquals } from "@ende/assert";

const array = [null, "a", "b"];
const result = firstNotNullishOf(array, (value, index) => index === 2 ? value : null);

assertEquals(result, "b");