mixin

export const mixin = <T>(target, sub, params = null): T => {
    // IMPORTANT: mixin is designed to function like Object.assign, just respects accessors
    // grab enumerable properties of the target object
    const keys = Object.keys(sub);
    keys.forEach((prop) => {
        const methodDef = Object.getOwnPropertyDescriptor(sub, prop);
        // check if this property uses accessor methods (Object.assign can't do this!)
        if (methodDef && (methodDef.get || methodDef.set)) {
            // yep
            addProperty(target, prop, Object.getOwnPropertyDescriptor(sub, prop).get,
                Object.getOwnPropertyDescriptor(sub, prop).set);
        } else {
            // nope
            target[prop] = sub[prop];
        }
    });
    return target;
};