Web and Mobile has many frameworks(JS/native) that can be used to solve similar problems. I am wondering how we can write code that can be re-written quickly on

Web and Mobile has many frameworks(JS/native) that can be used to solve similar problems. I am wondering how we can write code that can be re-written quickly on other frameworks as a metrics of performance tests. I definitely think that developers should test there code/app on slower/older phones. A performance mindset creates better scalable tech and can save the company a lot of money in the long run and at the same time can be a core of user experience