match-iz/dates/utils.mjs

A tiny pattern-matching library in the style of the TC39 proposal

import { isDate } from 'match-iz'

export const ifDate = fn => value => isDate(value) && fn(value)
export const byIndex = idx => (_, i) => i === idx
export const byLastIndex = idx => (_, i, arr) => i === arr.length + idx

/**
 * @param {number} start
 * @param {number} end
 * @returns {Iterable<number>}
 */
export function* range(start, end) {
  for (let i = start; i <= end; i++) yield i
}

export const dateSet =
  date =>
  fnName =>
  (...args) =>
    new Date(new Date(date)[`set${fnName}`](...args))