Nested mixin in JS

Question

I want to create a mixin that creates nested objects on the object that it mixes into.

For example

const mixin = {
  top: {
    middle: {
     bottom: () => {
         console.log(`Hello ${this.name}`);
       }
     }
  }
};

const objectToBeMixed = {
  name: 'Fred Bloggs'
};

Object.assign(objectToBeMixed, mixin);

objectToBeMixed.top.middle.bottom(); // Prints "Hello Fred Blogs"

Does anyone have an idea how to go about this, so that the "this" is bound to the objectToBeMixed?

Answer 1

That's not how you implement mixins. Instead of using a simple object, use a function that accepts context and merges the objects:

const mixin = context => Object.assign(context, {
  top: {
    middle: {
      bottom: () => {
        console.log(`Hello ${context.name}`);
      }
    }
  }
});

const objectToBeMixed = {
  name: 'Fred Bloggs'
};

mixin(objectToBeMixed);

objectToBeMixed.top.middle.bottom(); // Prints "Hello Fred Blogs"