Parse Dutch written date

parse-dutch-written-date.ts

"use strict";
function findMonth(s) {
    var MONTHS = ['januari', 'februari', 'maart', 'april',
        'mei', 'juni', 'juli', 'augustus', 'september',
        'oktober', 'november', 'december'];
    return MONTHS.reduce(function (result, month, index) {
        var i = s.indexOf(month);
        if (i >= 0) {
            return [month, index, i];
        }
        else {
            return result;
        }
    }, undefined);
}
function parseNumberBelow100(s) {
    var NUMBERS = ['een', 'twee', 'drie', 'vier', 'vijf', 'zes', 'zeven', 'acht', 'negen', 'tien',
        'elf', 'twaalf', 'dertien', 'veertien', 'vijftien',
        'zestien', 'zeventien', 'achttien', 'negentien'];
    var UNITS = ['een', 'twee', 'drie', 'vier', 'vijf', 'zes', 'zeven', 'acht', 'negen'];
    var TENS = ['twintig', 'dertig', 'veertig', 'vijftig', 'zestig', 'zeventig',
        'tachtig', 'negentig'];
    var index = NUMBERS.indexOf(s);
    if (index >= 0) {
        return index + 1;
    }
    index = TENS.findIndex(function (ten) { return s === ten; });
    if (index >= 0) {
        return (index + 2) * 10;
    }
    index = TENS.reduce(function (result, ten, tenIndex) {
        var unitIndex = UNITS.findIndex(function (unit) { return s === unit + 'en' + ten; });
        if (unitIndex >= 0) {
            return (tenIndex + 2) * 10 + (unitIndex + 1);
        }
        else {
            return result;
        }
    }, undefined);
    return index;
}
function parseDay(s) {
    return parseNumberBelow100(s);
}
function parseYear(s) {
    var hundreds = 0;
    var thousands = 0;
    var restIndex = -1;
    var rest = 0;
    var index100 = s.indexOf('honderd');
    if (index100 === 0) {
        hundreds = 1;
    }
    else if (index100 > 0) {
        hundreds = parseNumberBelow100(s.substring(0, index100));
    }
    else {
        var index1000 = s.indexOf('duizend');
        if (index1000 === 0) {
            thousands = 1;
        }
        else if (index1000 > 0) {
            thousands = parseNumberBelow100(s.substring(0, index1000));
        }
    }
    if (index100 >= 0) {
        restIndex = index100 + 7;
    }
    else if (index1000 >= 0) {
        restIndex = index1000 + 7;
    }
    if (restIndex !== -1 && restIndex < s.length) {
        rest = parseNumberBelow100(s.substring(restIndex).trim());
    }
    return (thousands * 1000) + (hundreds * 100) + rest;
}
function parseDate(s) {
    var monthInfo = findMonth(s);
    if (monthInfo) {
        var monthStr = monthInfo[0], month = monthInfo[1], monthPos = monthInfo[2];
        var dayStr = s.substring(0, monthPos).trim();
        var day = parseDay(dayStr);
        var yearStr = s.substring(monthPos + monthStr.length).trim();
        var year = parseYear(yearStr);
    }
    return new Date(year, month, day);
}
console.log(parseDate('negenentwintig oktober negentienhonderdvierenzeventig').toString());
console.log(parseDate('twaalf januari negentienhonderd').toString());
console.log(parseDate('eenendertig maart tweeduizend veertien').toString());
console.log(parseDate('drie december tweeduizend').toString());