@lou.codes/iterables/dist/asynchronous/join.js

🔁 Iterable and AsyncIterable utils

import { EMPTY_STRING } from "@lou.codes/constants/empty.js";
import { awaitableHandler } from "@lou.codes/utils";
import { reduce } from "./reduce.js";
/**
 * Takes a `separator` string and a iterable or asynchronous iterable and
 * returns a string with the concatenation of all the elements separated by the
 * `separator`.
 *
 * @category Asynchronous Reducers
 * @example
 * ```typescript
 * const joinWithSpaces = join(" ");
 * joinWithSpaces([1, 2, 3]); // "1 2 3"
 * ```
 * @param separator String to use as separator.
 * @returns Curried function with `separator` in context.
 */
export const join = separator => iterable =>
	awaitableHandler(string => string ?? EMPTY_STRING)(
		reduce(
			item => string =>
				`${string ?? EMPTY_STRING}${string === undefined ? EMPTY_STRING : separator}${item}`,
		)(undefined)(iterable),
	);