TableFilter/src/date.js

/**
 * Date utilities
 */

/**
 * Verifies passed formatted date string is valid
 * @param  {String}  dateStr Formatted date string
 * @param  {String}  format accepted formats: 'DMY', 'MDY', 'YMD', 'DDMMMYYYY'
 * @return {Boolean}
 */
export const isValidDate = (dateStr, format) => {
    if (!format) {
        format = 'DMY';
    }
    format = format.toUpperCase();
    if (format.length !== 3) {
        if (format === 'DDMMMYYYY') {
            let d = formatDate(dateStr, format);
            dateStr = d.getDate() + '/' + (d.getMonth() + 1) + '/' +
                d.getFullYear();
            format = 'DMY';
        }
    }
    if ((format.indexOf('M') === -1) || (format.indexOf('D') === -1) ||
        (format.indexOf('Y') === -1)) {
        format = 'DMY';
    }
    let reg1, reg2;
    // If the year is first
    if (format.substring(0, 1) === 'Y') {
        reg1 = /^\d{2}(\-|\/|\.)\d{1,2}\1\d{1,2}$/;
        reg2 = /^\d{4}(\-|\/|\.)\d{1,2}\1\d{1,2}$/;
    } else if (format.substring(1, 2) === 'Y') { // If the year is second
        reg1 = /^\d{1,2}(\-|\/|\.)\d{2}\1\d{1,2}$/;
        reg2 = /^\d{1,2}(\-|\/|\.)\d{4}\1\d{1,2}$/;
    } else { // The year must be third
        reg1 = /^\d{1,2}(\-|\/|\.)\d{1,2}\1\d{2}$/;
        reg2 = /^\d{1,2}(\-|\/|\.)\d{1,2}\1\d{4}$/;
    }
    // If it doesn't conform to the right format (with either a 2 digit year
    // or 4 digit year), fail
    if (reg1.test(dateStr) === false && reg2.test(dateStr) === false) {
        return false;
    }
    // Split into 3 parts based on what the divider was
    let parts = dateStr.split(RegExp.$1);
    let mm, dd, yy;
    // Check to see if the 3 parts end up making a valid date
    if (format.substring(0, 1) === 'M') {
        mm = parts[0];
    } else if (format.substring(1, 2) === 'M') {
        mm = parts[1];
    } else {
        mm = parts[2];
    }
    if (format.substring(0, 1) === 'D') {
        dd = parts[0];
    } else if (format.substring(1, 2) === 'D') {
        dd = parts[1];
    } else {
        dd = parts[2];
    }
    if (format.substring(0, 1) === 'Y') {
        yy = parts[0];
    } else if (format.substring(1, 2) === 'Y') {
        yy = parts[1];
    } else {
        yy = parts[2];
    }
    if (parseInt(yy, 10) <= 50) {
        yy = (parseInt(yy, 10) + 2000).toString();
    }
    if (parseInt(yy, 10) <= 99) {
        yy = (parseInt(yy, 10) + 1900).toString();
    }
    let dt = new Date(
        parseInt(yy, 10), parseInt(mm, 10) - 1, parseInt(dd, 10),
        0, 0, 0, 0);
    if (parseInt(dd, 10) !== dt.getDate()) {
        return false;
    }
    if (parseInt(mm, 10) - 1 !== dt.getMonth()) {
        return false;
    }
    return true;
}

/**
 * Converts formatted date into a Date object
 * @param  {String} dateStr Formatted date string
 * @param  {String} format accepted formats: 'DMY', 'MDY', 'YMD', 'DDMMMYYYY'
 * @return {Object} date object
 */
export const formatDate = (dateStr, formatStr) => {
    if (!formatStr) {
        formatStr = 'DMY';
    }
    if (!dateStr || dateStr === '') {
        return new Date(1001, 0, 1);
    }
    let oDate;
    let parts;

    switch (formatStr.toUpperCase()) {
        case 'DDMMMYYYY':
            parts = dateStr.replace(/[- \/.]/g, ' ').split(' ');
            oDate = new Date(y2kDate(parts[2]), mmm2mm(parts[1]) - 1, parts[0]);
            break;
        case 'DMY':
            /* eslint-disable */
            parts = dateStr.replace(
                /^(0?[1-9]|[12][0-9]|3[01])([- \/.])(0?[1-9]|1[012])([- \/.])((\d\d)?\d\d)$/, '$1 $3 $5').split(' ');
            oDate = new Date(y2kDate(parts[2]), parts[1] - 1, parts[0]);
            /* eslint-enable */
            break;
        case 'MDY':
            /* eslint-disable */
            parts = dateStr.replace(
                /^(0?[1-9]|1[012])([- \/.])(0?[1-9]|[12][0-9]|3[01])([- \/.])((\d\d)?\d\d)$/, '$1 $3 $5').split(' ');
            oDate = new Date(y2kDate(parts[2]), parts[0] - 1, parts[1]);
            /* eslint-enable */
            break;
        case 'YMD':
            /* eslint-disable */
            parts = dateStr.replace(/^((\d\d)?\d\d)([- \/.])(0?[1-9]|1[012])([- \/.])(0?[1-9]|[12][0-9]|3[01])$/, '$1 $4 $6').split(' ');
            oDate = new Date(y2kDate(parts[0]), parts[1] - 1, parts[2]);
            /* eslint-enable */
            break;
        default: //in case format is not correct
            /* eslint-disable */
            parts = dateStr.replace(/^(0?[1-9]|[12][0-9]|3[01])([- \/.])(0?[1-9]|1[012])([- \/.])((\d\d)?\d\d)$/, '$1 $3 $5').split(' ');
            oDate = new Date(y2kDate(parts[2]), parts[1] - 1, parts[0]);
            /* eslint-enable */
            break;
    }
    return oDate;
}

function y2kDate(yr) {
    if (yr === undefined) {
        return 0;
    }
    if (yr.length > 2) {
        return yr;
    }
    let y;
    //>50 belong to 1900
    if (yr <= 99 && yr > 50) {
        y = '19' + yr;
    }
    //<50 belong to 2000
    if (yr < 50 || yr === '00') {
        y = '20' + yr;
    }
    return y;
}

function mmm2mm(mmm) {
    if (mmm === undefined) {
        return 0;
    }
    let mondigit;
    let MONTH_NAMES = [
        'january', 'february', 'march', 'april', 'may', 'june', 'july',
        'august', 'september', 'october', 'november', 'december',
        'jan', 'feb', 'mar', 'apr', 'may', 'jun', 'jul', 'aug', 'sep', 'oct',
        'nov', 'dec'
    ];
    for (let m_i = 0; m_i < MONTH_NAMES.length; m_i++) {
        let month_name = MONTH_NAMES[m_i];
        if (mmm.toLowerCase() === month_name) {
            mondigit = m_i + 1;
            break;
        }
    }
    if (mondigit > 11 || mondigit < 23) {
        mondigit = mondigit - 12;
    }
    if (mondigit < 1 || mondigit > 12) {
        return 0;
    }
    return mondigit;
}