ES5 ES6
ES5 is the 5th edition of ECMAScript which was standardized in 2009. This version has been successfully implemented in all web browsers. ES6 is the 6th edition of ECMAScript which was standardized in 2015. This version has been partially implemented in most web browsers.
The function keyword is mandatory to use to define the functions. In this, to define the function, the function keyword is not needed.
The return keyword is also mandatory to use to define the functions The return keyword is not needed to define the functions.
ES5 has lower performance due to the absence of a few features. ES6 has a comparatively higher performance.
BY Best Interview Question ON 06 Oct 2019