sequential async

sequential-async-throws.js

/**
 * Run a series of async/promisifed functions sequentially,
 * returning an array of results.
 * Throws any exceptions.
 *
 * example:
 * const values = [1, 2, 3, 4, 5];
 * const callback = async (value) => await someAsyncThing(value)
 * const result = await sequentialAsync(values, callback);
 *
 * @param  {Iterable} values
 * @param  {Function} callback
 * @return {Array}    array of results
 */
const sequentialAsync = async (iterator, callback) =>
  iterator.reduce(async (acc, value) => {
    const results = await acc;
    return [...results, await callback(value)];
  }, []);