cherrypulp / js-mixin

export default function mixin(MixTrait, ...traits) {

    class Mix extends MixTrait {

        constructor(...args) {

            super(...args);

            // copy properties and symbols

            traits.forEach((Trait) => {

                const instance = new Trait(...args);

                copyProps(this, instance);

            });

        }

    }

    // copy static properties and symbols

    traits.forEach((Trait) => {

        copyProps(Mix.prototype, Trait.prototype);

        copyProps(Mix, Trait);

    });

    return Mix;

}

/**

 * Copy properties from source to target.

 * @param target

 * @param source

 */

function copyProps(target, source) {

    const properties = Object.getOwnPropertyNames(source);

    properties

        .concat(Object.getOwnPropertySymbols(source))

        .filter((key) => !key.match(/^(?:constructor|prototype|arguments|caller|name|bind|call|apply|toString|length)$/))

        .forEach((key) => {

            const props = Object.getOwnPropertyDescriptor(source, key);

            Object.defineProperty(target, key, props);

        });

}