code: function(mime, target) {
  		target = target || this.cwd().hash;
  		var res   = true, // default is allow
  			mimeChecker = this.option('uploadMime', target),
  			allow,
  			deny,
  			check = function(checker) {
  				var ret = false;
  				if (typeof checker === 'string' && checker.toLowerCase() === 'all') {
  					ret = true;
  				} else if (Array.isArray(checker) && checker.length) {
  					$.each(checker, function(i, v) {
  						v = v.toLowerCase();
  						if (v === 'all' || mime.indexOf(v) === 0) {
  							ret = true;
  							return false;
  						}
  					});
  				}
  				return ret;
  			};
  		if (mime && $.isPlainObject(mimeChecker)) {
  			mime = mime.toLowerCase();
  			allow = check(mimeChecker.allow);
  			deny = check(mimeChecker.deny);
  			if (mimeChecker.firstOrder === 'allow') {
  				res = false; // default is deny
  				if (! deny && allow === true) { // match only allow
  					res = true;
  				}
  			} else {
  				res = true; // default is allow
  				if (deny === true && ! allow) { // match only deny
  					res = false;
  				}
  			}
  		}
  		return res;
  	}
docs: Return boolean that uploadable MIME type into target folder
  
  @param  String  mime    MIME type
  @param  String  target  target folder hash
  @return Bool