在 javascript 对象中，“静态”函数和原型函数是否共享相同的命名空间？

Question

regardless of the wisdom of such a naming scheme, is the following valid?

var F = function() {
  this.f1 = function() {}
}
F.f1 = function() {}

// "static" call
var v1 = F.f1();

// prototype call
var f = new F();
var v2 = f.f1();

it seems it should be ok since, for example, var and this variables within an object function do not share the same space.

Answer 1

Yes, that is valid.

In your example, F is a function which you assign a property called f1 which is a function itself. If you were to change the code to read f = new F() , then f is an object which inherits from F 's prototype, but they're still two distinct objects.

Answer 2

It is valid.
Like the others have stated, there are no prototype related issues here.
You are attaching 2 propertyes to 2 different objects:

• the so called "static" function is attached to the function definition (F)
• the so called "public" function is attached to the object returned by the constructor (new F())

So, since F !== new F() , they are 2 different thing with different props.

If you want to make use of the prototypal inheritance, you can consider the following example:

 var F = function(){}
 // function visible to all of F's instances
 F.prototype.f1 = function(){console.log("I'm inherited!");}
 // a so called "static" function
 F.f1 = function(){console.log("I'm static!");}
 var instance1 = new F();
 var instance2 = new F();
 // function visible only to this instance of F
 instance1.f1 = function(){console.log("I'm visible only to this instance of F");}