JamieMason/Jasmine-Matchers

import { toBeString } from './toBeString';
import { toBeValidDate } from './toBeValidDate';

export type ToBeIso8601 = (expectationFailOutput?: any) => boolean;

declare global {
  namespace jasmine {
    interface Matchers<T> {
      toBeIso8601: ToBeIso8601;
    }
  }
}

export const toBeIso8601: ToBeIso8601 = (actual) =>
  toBeString(actual) &&
  (isMatch('1999-12-31', actual) ||
    isMatch('1999-12-31T23:59', actual) ||
    isMatch('1999-12-31T23:59:59', actual) ||
    isMatch('1999-12-31T23:59:59.000', actual) ||
    isMatch('1999-12-31T23:59:59.000Z', actual)) &&
  toBeValidDate(new Date(actual));

function isMatch(pattern, actual) {
  const patterns = {
    '1999-12-31': /^(\d{4})-(\d{2})-(\d{2})$/,
    '1999-12-31T23:59': /^(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2})$/,
    '1999-12-31T23:59:59': /^(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2})$/,
    '1999-12-31T23:59:59.000': /^(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2})\.(\d{3})$/,
    '1999-12-31T23:59:59.000Z': /^(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2})\.(\d{3})Z$/,
  };
  return actual.search(patterns[pattern]) !== -1;
}