function parse$a(str) {
  str = String(str);
  if (str.length > 100) {
    return;
  }
  var match = /^(-?(?:\d+)?\.?\d+) *(milliseconds?|msecs?|ms|seconds?|secs?|s|minutes?|mins?|m|hours?|hrs?|h|days?|d|weeks?|w|years?|yrs?|y)?$/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 'weeks':
    case 'week':
    case 'w':
      return n * w;
    case 'days':
    case 'day':
    case 'd':
      return n * d;
    case 'hours':
    case 'hour':
    case 'hrs':
    case 'hr':
    case 'h':
      return n * h$1;
    case 'minutes':
    case 'minute':
    case 'mins':
    case 'min':
    case 'm':
      return n * m$1;
    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;
  }
}
Set _Content-Type_ response header with `type` through `mime.lookup()`
when it does not contain "/", or set the Content-Type to `type` otherwise.

Examples:

    res.type('.html');
    res.type('html');
    res.type('json');
    res.type('application/json');
    res.type('png');

@param {String} type
@return {ServerResponse} for chaining
@public