function cache(options, compiled) {
	  // cachable
	  if (compiled && options.filename && options.cache) {
	    delete readCache[options.filename];
	    cacheStore[options.filename] = compiled;
	    return compiled;
	  }

	  // check cache
	  if (options.filename && options.cache) {
	    return cacheStore[options.filename];
	  }

	  return compiled;
	}
Conditionally cache `compiled` template based
on the `options` filename and `.cache` boolean.

@param {Object} options
@param {Function} compiled
@return {Function}
@api private