Any other solution for context resolution this in promises except bind
<p>Any lateral solution in this case when I need to know which class I'm in without using bind.</p>

<pre><code>function Customer() {}
Customer.prototype.say = function() {
    console.log("I'm " + this.constructor.TYPE);
};
Customer.TYPE = 'customer';

function Product() {}
Product.prototype.say = function() {
    console.log("I'm " + this.constructor.TYPE);
};
Product.TYPE = 'product';

var customer = new Customer();
var product = new Product();

//cleaner interface
Promise.resolve()
    .then(customer.say) //I'm undefined
    .then(product.say) //I'm undefined


//works but looking for a solution using cleaner interface like above
//any lateral thinking
Promise.resolve()
    .then(customer.say.bind(customer)) //I'm customer
    .then(product.say.bind(product))  //I'm product
</code></pre>

<p>I'm looking for non-bind based solution, any lateral thinking based ideas?</p>

<p>It's an SDK I'm developing so want to give a cleaner interface and use to clients.</p>