function requireMs () {
	if (hasRequiredMs) return ms$2;
	hasRequiredMs = 1;
	var s = 1000;
	var m = s * 60;
	var h = m * 60;
	var d = h * 24;
	var y = d * 365.25;

	/**
	 * Parse or format the given `val`.
	 *
	 * Options:
	 *
	 *  - `long` verbose formatting [false]
	 *
	 * @param {String|Number} val
	 * @param {Object} [options]
	 * @throws {Error} throw an error if val is not a non-empty string or a number
	 * @return {String|Number}
	 * @api public
	 */

	ms$2 = function(val, options) {
	  options = options || {};
	  var type = typeof val;
	  if (type === 'string' && val.length > 0) {
	    return parse(val);
	  } else if (type === 'number' && isNaN(val) === false) {
	    return options.long ? fmtLong(val) : fmtShort(val);
	  }
	  throw new Error(
	    'val is not a non-empty string or a valid number. val=' +
	      JSON.stringify(val)
	  );
	};

	/**
	 * Parse the given `str` and return milliseconds.
	 *
	 * @param {String} str
	 * @return {Number}
	 * @api private
	 */

	function parse(str) {
	  str = String(str);
	  if (str.length > 100) {
	    return;
	  }
	  var match = /^((?:\d+)?\.?\d+) *(milliseconds?|msecs?|ms|seconds?|secs?|s|minutes?|mins?|m|hours?|hrs?|h|days?|d|years?|yrs?|y)?$/i.exec(
	    str
	  );
	  if (!match) {
	    return;
	  }
	  var n = parseFloat(match[1]);
	  var type = (match[2] || 'ms').toLowerCase();
	  switch (type) {
	    case 'years':
	    case 'year':
	    case 'yrs':
	    case 'yr':
	    case 'y':
	      return n * y;
	    case 'days':
	    case 'day':
	    case 'd':
	      return n * d;
	    case 'hours':
	    case 'hour':
	    case 'hrs':
	    case 'hr':
	    case 'h':
	      return n * h;
	    case 'minutes':
	    case 'minute':
	    case 'mins':
	    case 'min':
	    case 'm':
	      return n * m;
	    case 'seconds':
	    case 'second':
	    case 'secs':
	    case 'sec':
	    case 's':
	      return n * s;
	    case 'milliseconds':
	    case 'millisecond':
	    case 'msecs':
	    case 'msec':
	    case 'ms':
	      return n;
	    default:
	      return undefined;
	  }
	}

	/**
	 * Short format for `ms`.
	 *
	 * @param {Number} ms
	 * @return {String}
	 * @api private
	 */

	function fmtShort(ms) {
	  if (ms >= d) {
	    return Math.round(ms / d) + 'd';
	  }
	  if (ms >= h) {
	    return Math.round(ms / h) + 'h';
	  }
	  if (ms >= m) {
	    return Math.round(ms / m) + 'm';
	  }
	  if (ms >= s) {
	    return Math.round(ms / s) + 's';
	  }
	  return ms + 'ms';
	}

	/**
	 * Long format for `ms`.
	 *
	 * @param {Number} ms
	 * @return {String}
	 * @api private
	 */

	function fmtLong(ms) {
	  return plural(ms, d, 'day') ||
	    plural(ms, h, 'hour') ||
	    plural(ms, m, 'minute') ||
	    plural(ms, s, 'second') ||
	    ms + ' ms';
	}

	/**
	 * Pluralization helper.
	 */

	function plural(ms, n, name) {
	  if (ms < n) {
	    return;
	  }
	  if (ms < n * 1.5) {
	    return Math.floor(ms / n) + ' ' + name;
	  }
	  return Math.ceil(ms / n) + ' ' + name + 's';
	}
	return ms$2;
}
Enable `setting`.

@param {String} setting
@return {app} for chaining
@public