In the context of the class, it loops through an array where the public methods are described. For each of them, it creates a new key to the object `this` with the name of the method and a function as value. Note that the `this` key word here refers to the class itself, since it's inside an arrow-function which does not have its own `this`. When dealing with classes, since Javascript does not differentiate between private and public, that's all you need to expose public methods programmatically.