It used to be called Ecmascript 6 (aka ES6), but the name was changed to help enforce a more frequent update. So, it changed from ES6 to Ecmascript 2015 (aka ES

It used to be called Ecmascript 6 (aka ES6), but the name was changed to help enforce a more frequent update. So, it changed from ES6 to Ecmascript 2015 (aka ES2015).