Multi-line regexps in JS made easy

gist.js

const regexp = (xs, ...ys) => (xs2, ...ys2) =>
    new RegExp(
        String.raw(xs, ...ys).replace(
            // Find additional escape sequences,
            // spaces, line breaks, comments:
            /\\[#\n ]|#.*$|[\n ]/gm,
            // Remove spaces, line breaks, comments,
            // unescape additional sequences:
            x => (x[0] === '\\' ? x[1] : ''),
        ),
        String.raw(xs2, ...ys2),
    );

usage.js

const date = regexp`^
    (?<year>  \d{4}) - # Year
    (?<month> \d{2}) - # Month
    (?<day>   \d{2})   # Day
$``u`; // ← Flags.

const { year, month, day } = date.exec('2018-03-29').groups;

console.log(`${parseInt(month)}/${parseInt(day)}/${parseInt(year)}`); // 3/29/2018