JavaScript Mixin

a class that contains methods for use by other classes without having to be the parent class of those other classes.

// mixin
let sayHiMixin = {
  sayHi() {
    alert(`Hello ${this.name}`);
  },
  sayBye() {
    alert(`Bye ${this.name}`);
  }
};
 
// usage:
class User {
  constructor(name) {
    this.name = name;
  }
}
 
// copy the methods
Object.assign(User.prototype, sayHiMixin);
 
// now User can say hi
new User("Dude").sayHi(); // Hello Dude!