@yadah/dedupe-mixin v0.2.0

dedupe-mixin

A mixin is a function which returns a class that extends a provided "super class".

(superclass) => class extends superclass {};

The dedupe() function is a wrapper for mixins to allow a mixin to be used multiple times without duplicating behaviour.

The typical usage is like:

// CustomMixin.js
import dedupe from "@yadah/dedupe-mixin";

function CustomMixin(superclass) {
  return class Custom extends superclass {
    fn() {
      super.fn();
      console.log("inside Custom.fn");
    }
  };
}
export default CustomMixin |> dedupe(%);

If this mixin is then used multiple times in the some mixin chain, it will only appear once

import CustomMixin from "./CustomMixin.js";

class superclass {
  fn() {}
}

class Example extends (superclass |> CustomMixin(%) |> CustomMixin(%)) {}

new Example().fn();
// logs "inside Custom.fn" (once only)

dedupe() also adds a method to the wrapped mixin function that allows checking if a class includes the mixin:

CustomMixin.extends(Example);
// true