createNamedObject.js

function createNamedObject( fn, obj ) {	
	return _.extend(new fn(), obj)
}

var api = {
	get: function() {},
	set: function() {},
	save: function() {}
}
 
var namedApi = createNamedObject( function MyCustomApi(){}, api)

console.log( api )
// > Object {get: function, set: function, save: function}
console.log( namedApi )
// > MyCustomApi {get: function, set: function, save: function}