Question

I’m just a newer to JavaScript. I want to write a JS template class like C++. for example:

template <typename T>
class A
{
public:
    A(T x)
    {
        this.a=x;
    }
    ~A()
    {

    }
    void print()
    {
        std::cout<<a<<std::endl;
    }
private:
    T a;
};

We can use this class like this:

A<int> test(2);
test.print();

For C++, it’s simple. But in JS, how it can be explained? Thanks very much.

Answer 1

You could do this:

var A = function ( x ) {
    var a = x;
    this.print = function () {
        console.log(a);
    };
};

var test = new A(2);
test.print(); // -> 2

In this case, the variable a is private, the function print is public (as is any other property of this), and A is the constructor function for the template (prototype object).