Mixins Available since v0.8

@aedart/support/mixins offers an adaptation of Justin Fagnani'smixwith.js package (originally licensed under Apache License 2.0).

import { mix, Mixin } from "@aedart/support/mixins";

// Define mixin
const NameMixin = Mixin((superclass) => class extends superclass {

    #name;
    
    set name(value) {
        this.#name = value;
    }
    
    get name() {
        return this.#name;
    }
});

// Apply mixin...
class Item extends mix().with(
    NameMixin
) {
    // ...not shown...    
}

// ...Later in your application
const item = new Item();
item.name = 'My Item';

console.log(item.name); // My Item

See also Concerns as an alternative.