import escapeRegExp = require('lodash/escapeRegExp'); import memoize = require('lodash/memoize'); import * as moment from 'moment-timezone'; // When using YY format, use a consistent interpretation in datepicker and in moment parsing: add // 2000 if the result is at most 10 years greater than the current year; otherwise add 1900. See // https://bootstrap-datepicker.readthedocs.io/en/latest/options.html#assumenearbyyear and // "Parsing two digit years" in https://momentjs.com/docs/#/parsing/string-format/. export const TWO_DIGIT_YEAR_THRESHOLD = 10; const MAX_TWO_DIGIT_YEAR = new Date().getFullYear() + TWO_DIGIT_YEAR_THRESHOLD - 2000; // Moment suggests that overriding this is fine, but we need to force TypeScript to allow it. (moment as any).parseTwoDigitYear = function(yearString: string): number { const year = parseInt(yearString, 10); return year + (year > MAX_TWO_DIGIT_YEAR ? 1900 : 2000); }; // Order of formats to try if the date cannot be parsed as the currently set format. // Formats are parsed in momentjs strict mode, but separator matching and the MM/DD // two digit requirement are ignored. Also, partial completion is permitted, so formats // may match even if only beginning elements are provided. // TODO: These should be affected by the user's locale/settings. // TODO: We may want to consider adding default time formats as well to support more // time formats. const PARSER_FORMATS: string[] = [ 'M D YYYY', 'M D YY', 'M D', 'M', 'MMMM D YYYY', 'MMMM D', 'MMMM Do YYYY', 'MMMM Do', 'D MMMM YYYY', 'D MMMM', 'Do MMMM YYYY', 'Do MMMM', 'MMMM', 'MMM D YYYY', 'MMM D', 'MMM Do YYYY', 'MMM Do', 'D MMM YYYY', 'D MMM', 'Do MMM YYYY', 'Do MMM', 'MMM', 'YYYY M D', 'YYYY M', 'YYYY', 'D M YYYY', 'D M YY', 'D M', 'D' ]; const UNAMBIGUOUS_FORMATS = PARSER_FORMATS.filter(f => f.includes("MMM")); const TIME_REGEX = /^(?:(\d\d?)(?::(\d\d?)(?::(\d\d?))?)?|(\d\d?)(\d\d))\s*([ap]m?)?$/i; // [^a-zA-Z] because no letters are allowed directly before the abbreviation const UTC_REGEX = /[^a-zA-Z](UTC?|GMT|Z)$/i; const NUMERIC_TZ_REGEX = /([+-]\d\d?)(?::?(\d\d))?$/i; // Not picky about separators, so replace them in the date and format strings to be spaces. const SEPARATORS = /[\W_]+/g; const tzAbbreviations = memoize((tzName: string): RegExp => { // Some abbreviations are just e.g. +05 // and escaping the + seems better than filtering const abbreviations = new Set(moment.tz.zone(tzName)!.abbrs.map(escapeRegExp)); const union = [...abbreviations].join('|'); // [^a-zA-Z] because no letters are allowed directly before the abbreviation // so for example CEST won't match even if EST does return new RegExp(`[^a-zA-Z](${union})$`, 'i'); }); interface ParseOptions { time?: string; dateFormat?: string; timeFormat?: string; timezone?: string; } /** * parseDate - Attempts to parse a date string using several common formats. Returns the * timestamp of the parsed date in seconds since epoch, or returns null on failure. * @param {String} date - The date string to parse. * @param {String} options.dateFormat - The preferred momentjs format to use to parse the * date. This is attempted before the default formats. * @param {String} options.time - The time string to parse. * @param {String} options.timeFormat - The momentjs format to use to parse the time. This * must be given if options.time is given. * @param {String} options.timezone - The timezone string for the date/time, which affects * the resulting timestamp. */ export function parseDate(date: string, options: ParseOptions = {}): number | null { // If no date, return null. if (!date) { return null; } const dateFormats = PARSER_FORMATS.slice(); // If a preferred parse format is given, set that to be the first parser used. if (options.dateFormat) { dateFormats.unshift(..._buildVariations(options.dateFormat, date)); } const cleanDate = date.replace(SEPARATORS, ' '); let datetime = cleanDate.trim(); let timeformat = ''; if (options.time) { const standardTime = standardizeTime(options.time, options.timezone!); if (!standardTime) { return null; } const {time, tzOffset} = standardTime; datetime += ' ' + time + tzOffset; timeformat = ' HH:mm:ss' + (tzOffset ? 'Z' : ''); } for (const f of dateFormats) { const fullFormat = f + timeformat; const m = moment.tz(datetime, fullFormat, true, options.timezone || 'UTC'); if (m.isValid()) { return m.valueOf() / 1000; } } return null; } /** * Similar to parseDate, with these differences: * - Only for a date (no time part) * - Only falls back to UNAMBIGUOUS_FORMATS, not the full PARSER_FORMATS * - Optionally adds all dates which match some format to `results`, otherwise returns first match. * This is safer so it can be used for parsing when pasting a large number of dates * and won't silently swap around day and month. */ export function parseDateStrict(date: string, dateFormat: string | null, results?: Set): number | undefined { if (!date) { return; } const dateFormats = []; if (dateFormat) { dateFormats.push(..._buildVariations(dateFormat, date)); } dateFormats.push(...UNAMBIGUOUS_FORMATS); const cleanDate = date.replace(SEPARATORS, ' ').trim(); for (const format of dateFormats) { const m = moment.tz(cleanDate, format, true, 'UTC'); if (m.isValid()) { const value = m.valueOf() / 1000; if (results) { results.add(value); } else { return value; } } } } // Helper function to get the partial format string based on the input. Momentjs has a feature // which allows defaulting to the current year, month and/or day if not accounted for in the // parser. We remove any parts of the parser not given in the input to take advantage of this // feature. function _getPartialFormat(input: string, format: string): string { // Define a regular expression to match contiguous non-separators. const re = /Y+|M+|D+|[a-zA-Z0-9]+/g; // Count the number of meaningful parts in the input. const numInputParts = input.match(re)?.length || 0; // Count the number of parts in the format string. let numFormatParts = format.match(re)?.length || 0; if (numFormatParts > numInputParts) { // Remove year from format first, to default to current year. if (/Y+/.test(format)) { format = format.replace(/Y+/, ' ').trim(); numFormatParts -= 1; } if (numFormatParts > numInputParts) { // Remove month from format next. format = format.replace(/M+/, ' ').trim(); } } return format; } // Moment non-strict mode is considered bad, as it's far too lax. But moment's strict mode is too // strict. We want to allow YY|YYYY for either year specifier, as well as M for MMM or MMMM month // specifiers. It's silly that we need to create multiple format variations to support this. function _buildVariations(dateFormat: string, date: string) { // Momentjs has an undesirable feature in strict mode where MM and DD // matches require two digit numbers. Change MM, DD to M, D. let format = dateFormat.replace(/MM+/g, m => (m === 'MM' ? 'M' : m)) .replace(/DD+/g, m => (m === 'DD' ? 'D' : m)) .replace(SEPARATORS, ' ') .trim(); // Allow the input date to end with a 4-digit year even if the format doesn't mention the year if ( format.includes("M") && format.includes("D") && !format.includes("Y") ) { format += " YYYY"; } format = _getPartialFormat(date, format); // Consider some alternatives to the preferred format. const variations = new Set([format]); const otherYear = format.replace(/Y{2,4}/, (m) => (m === 'YY' ? 'YYYY' : (m === 'YYYY' ? 'YY' : m))); variations.add(otherYear); variations.add(format.replace(/MMM+/, 'M')); if (otherYear !== format) { variations.add(otherYear.replace(/MMM+/, 'M')); } return variations; } // Based on private calculateOffset in moment source code. function calculateOffset(tzMatch: string[]): string { const [, hhOffset, mmOffset] = tzMatch; const sign = hhOffset.slice(0, 1); return sign + hhOffset.slice(1).padStart(2, '0') + ':' + (mmOffset || '0').padStart(2, '0'); } // Parses time of the form, roughly, HH[:MM[:SS]][am|pm] [TZ]. Returns the time in the // standardized HH:mm:ss format, and an offset string that's empty or is of the form [+-]HH:mm. // This turns out easier than coaxing moment to parse time sensibly and flexibly. function standardizeTime(timeString: string, timezone: string): { time: string, tzOffset: string } | undefined { let cleanTime = timeString.trim(); let tzMatch = UTC_REGEX.exec(cleanTime); let matchStart = 0; let tzOffset = ''; if (tzMatch) { tzOffset = '+00:00'; matchStart = tzMatch.index + 1; // skip [^a-zA-Z] at regex start } else { tzMatch = NUMERIC_TZ_REGEX.exec(cleanTime); if (tzMatch) { tzOffset = calculateOffset(tzMatch); matchStart = tzMatch.index; } else if (timezone) { // Abbreviations are simply stripped and ignored, so tzOffset is not set in this case tzMatch = tzAbbreviations(timezone).exec(cleanTime); if (tzMatch) { matchStart = tzMatch.index + 1; // skip [^a-zA-Z] at regex start } } } if (tzMatch) { cleanTime = cleanTime.slice(0, matchStart).trim(); } const match = TIME_REGEX.exec(cleanTime); if (match) { let hours = parseInt(match[1] || match[4], 10); const mm = (match[2] || match[5] || '0').padStart(2, '0'); const ss = (match[3] || '0').padStart(2, '0'); const ampm = (match[6] || '').toLowerCase(); if (hours < 12 && hours > 0 && ampm.startsWith('p')) { hours += 12; } else if (hours === 12 && ampm.startsWith('a')) { hours = 0; } const hh = String(hours).padStart(2, '0'); return {time: `${hh}:${mm}:${ss}`, tzOffset}; } }