TypeScript: Global static variable best practice

Question

I have this class where I need to increment a number each time the class is instantiated. I have found two ways to this where both ways works, but I am not sure yet on what is the best practice

1. declare the variable in the module scope

   module M {
     var count : number = 0;
     export class C {
       constructor() {
         count++;
       }
     }
   }
   

2. declare the variable in the class scope and access it on Class

   module M {
     export class C {
       static count : number = 0;
       constructor() {
         C.count++;  
       }
     }
   }
   

My take is example two as it does not adds the count variable in the module scope.

See also: C# incrementing static variables upon instantiation

Answer 1

Both of them are okay, but method 2 more self explanatory, which means its less confusing when your code get more complex unless you are using the count to increase each time you instantiate a class from that module then method 1 is the way to go.

I prefer to do it this way:

module M {
  export class C {
    static count : number = 0;
    constructor() {
      C.count++;  
    }
  }
}

Answer 2

Definitely method 2 since that is the class that is using the variable. So it should contain it.

In case 1 you are using a variable that will become confusing once you have more than one classes in there e.g:

module M {

  var count : number = 0;

  export class C {
    constructor() {
      count++;
    }
  }

  export class A{
  }
}