JITs aren't a panacea for everything. As the blog post said, if you want to avoid falling off a performance cliff you must write "CranskshaftScript" instead of

JITs aren't a panacea for everything. As the blog post said, if you want to avoid falling off a performance cliff you must write "CranskshaftScript" instead of Javascript. And the only way to be sure that the optimizer is content through a specialized profiler.