What is prototype syntax Prototype syntax is still useful. Before ECMAscript 6 the class keyword did not exist so developers had to use prototype syntax: function Name ( params ) { this . name = value ; // ... } ClassName . prototype . name = function ( params ) { // ... } // ... Enter fullscreen mode Exit fullscreen mode That was prototype syntax. why is it still useful If you are using a legacy environment where ECMAscript 6 doesn't exist. That's when prototype syntax becomes useful. Prototype syntax is in commonJS so you can use this in CJS(CommonJS) scripts. NOTE : modern CommonJS supports class so prototype syntax is still legacy by definition Why class exists class exists to make OOP(Object Oriented Programming) easier. Protoype syntax altho useful, is more complex and lengthy to use. even with minification it also introduced the constructor keyword classes introduced getters and setters with the new class syntax you can now use: class name { constructor ( params ) { this . name = value ; // ...…