JavaScript: How to create a new instance of a class without using the new keyword?
- by Alessandro Vernet
I think the following code will make the question clear.
// My class
var Class = function() { console.log("Constructor"); };
Class.prototype = { method: function() { console.log("Method");} }
// Creating an instance with new
var object1 = new Class();
object1.method();
console.log("New returned", object1);
// How to write a factory which can't use the new keyword?
function factory(clazz) {
// Assume this function can't see "Class", but only sees its parameter "clazz".
return clazz.call(); // Calls the constructor, but no new object is created
return clazz.new(); // Doesn't work because there is new() method
};
var object2 = factory(Class);
object2.method();
console.log("Factory returned", object2);
