displayDate.js

/**
 * Converts a Date or TimeStamp into a human readable format
 * @module {Function} utils/displayDate
 * @flow
 */
import memoizeWith from 'ramda/src/memoizeWith';
import identity from 'ramda/src/identity';
import pipe from 'ramda/src/pipe';
import ifElse from 'ramda/src/ifElse';
import useWith from 'ramda/src/useWith';
import equals from 'ramda/src/equals';
import inc from 'ramda/src/inc';
import length from 'ramda/src/length';
import join from 'ramda/src/join';
import converge from 'ramda/src/converge';
import toString from 'ramda/src/toString';
import unapply from 'ramda/src/unapply';
import curry from 'ramda/src/curry';
import translate from 'utils/translate';
import * as translations from 'constants/translations';

export type DateInput = Date | number | string;

type DisplayDateFn = (date?: DateInput | null) => string;

const doubleDigit = ifElse(
  useWith(equals(2), [length]),
  identity,
  n => `0${n}`,
);

// gets the prototype function of an object so it can be called against a value
const protoOf = curry((Obj, method, value, ...args) =>
  Obj.prototype[method].call(value, ...args));

const protoOfDate = protoOf(Date);

export const getDate: (date: Date) => string = pipe(
  protoOfDate('getDate'),
  toString,
  doubleDigit,
);

export const getMonth: (date: Date) => string = pipe(
  protoOfDate('getMonth'),
  inc, // month count is zero based
  toString,
  doubleDigit,
);

export const getYear: (date: Date) => string = pipe(
  protoOfDate('getFullYear'),
  toString,
);

/**
 * Converts a date to "yyyy-mm-dd" format
 * @param {Date} date - Date to convert
 * @returns {string} yyyy-mm-dd
 */
export const hyphenDate: (date: Date) => string = converge(
  pipe(unapply(identity), join('-')),
  [getYear, getMonth, getDate],
);

// Always returns a valid date
const createDate = (dateInput?: DateInput): Date => (dateInput
  ? new Date(dateInput)
  : new Date()
);

export const incDate = (dateInput?: DateInput, amount: number = 1): Date => {
  const next = createDate(dateInput);
  next.setDate(next.getDate() + amount);
  return next;
};

export const decDate = (dateInput?: DateInput, amount: number = 1): Date => {
  const next = createDate(dateInput);
  next.setDate(next.getDate() - amount);
  return next;
};

// validate the date input
const isValidDate = (date: Date): boolean => !isNaN(date);

export const createDateDisplay = (
  getDisplay: Date => string,
  invalidDisplay: string = translate(translations.NOT_AVAILABLE),
): DisplayDateFn => memoizeWith(identity, (dateInput: DateInput) => {
  if (dateInput) {
    const date = createDate(dateInput);
    if (isValidDate(date)) return getDisplay(date);
  }
  return invalidDisplay;
});

export const displayDate: DisplayDateFn = createDateDisplay(date => date.toLocaleDateString(), translate(translations.ONGOING));
export const displayTime: DisplayDateFn = createDateDisplay(date => date.toLocaleTimeString());
export const displayDateTime: DisplayDateFn = createDateDisplay(date => date.toLocaleString());
export const displayHyphenDate: DisplayDateFn = createDateDisplay(hyphenDate);

displayDate.date = displayDate;
displayDate.time = displayTime;
displayDate.dateTime = displayDateTime;
displayDate.create = createDateDisplay;
displayDate.hyphenDate = displayHyphenDate;

export default displayDate;