Symbol is a primitive type(not an object) included in the ECMAScript 2015(aka, ES6). We are already familiar with the existing primitive types like, Number, String and, Boolean. Like these primitive types, Symbols are also created via a factory function.
Symbol allows us to create unique identifiers. Every time we invoke Symbol(), a new unique symbol is created. Two symbols are not equal(they are unique) even when they have the same name.