MrSwitch / dare / #72

        if (typeof values === 'string') {

                if (values.indexOf('..') === -1) {

                        values = `${values}..${values}`;

                }

                let i = 0;

                // Out-of-scope cache for constructing correct format - CB

                let strCache = '';

                const a = values.split('..').map((str, index) => {

                        if (!str) {

                                return '';

                        }

                        // Pad the start of each subvalue - CB

                        const padded = str.split('-').map(el => el.padStart(2, '0'));

                        str = padded.join('-');

                        // Allow the format yyyy-mm-dd..dd by constructing the second timestamp - CB

                        if (

                                index === 1 &&

                                str.length === 2 &&

                                strCache.length &&

                                strCache.length === 10

                        ) {

                                str = strCache.slice(0, 8) + str;

                        }

                        strCache = str;

                        // Tidy up the ISO string

                        const _str = str.replace(/(?<hour>T\d+)$/, '$<hour>:00'); // Requires minutes with hours

                        const date = new Date(_str);

                        if (i++) {

                                const [, mm, dd, hh, i, s] = str.split(/\D+/);

                                if (!mm) {

                                        date.setFullYear(date.getFullYear() + 1);

                                } else if (!dd) {

                                        date.setMonth(date.getMonth() + 1);

                                } else if (!hh) {

                                        date.setDate(date.getDate() + 1);

                                } else if (!i) {

                                        date.setHours(date.getHours() + 1);

                                } else if (!s) {

                                        date.setMinutes(date.getMinutes() + 1);

                                }

                                // Wind back a second

                                if (!s) {

                                        date.setSeconds(date.getSeconds() - 1);

                                }

                        }

                        return date.toISOString().replace(/\.\d+Z/, '');

                });

                if (a[0] === a[1]) {

                        return a[0];

                }

                return a.join('..');

        }

        return values;

}