可能将javascript变量的作用域限定为一个函数，并且该函数对其自身进行递归调用？

Question

I am in a situation where I have a loop that is calling a function. The function will make recursive calls to itself once called.

Is there a way that I can scope a variable to the function and the chain of recursive calls generated from the first call?

Something like this:

for(var i=0;i<100;i++)
{
  myFunction();
}

function myFunction()
{
   var someNumber = 200;
   someNumber -= 10;
   if( someNumber > 0)
   {
      myFunction();
   }
}

where at the second iteration of the first call to someNumber would be 190 and not 200. Is this possible to accomplish?

If there is anything confusing here, please let me know.

Answer 1

while(var i=0;i<100;i++)
{
  myFunction(200);
}

function myFunction(someNumber)
{
   someNumber -= 10;
   if( someNumber > 0)
   {
      myFunction(someNumber);
   }
}

Answer 2

Yes, use an inner function to do the recursion:

for (var i = 0; i < 100; i++)
{
    myFunction();
}

function myFunction()
{
    var someNumber = 200;
    (function innerFunction()
    {
        someNumber -= 10;
        if( someNumber > 0)
        {
            innerFunction();
        }
    })();
};

Note, you have a syntax error. Your while needs to be for .

Edit: Perhaps your real code is different and calls for a recursive function, but your example would be much simpler by just using a loop:

function myFunction()
{
    for (var someNumber = 200; someNumber > 0; someNumber -= 10)
    {
    }
};

Answer 3

Yes and no--you should be able to accomplish the task by passing the value of the variable in as a parameter of myFunction . The first call will need to set the starting value, then pass it along for future invocations to modify.

while(var i=0;i<100;i++)
{
  myFunction();
}


function myFunction(seed) {
    if (seed == undefined)
    {
        seed = 200;
    }

    alert(seed);

    var newSeed = seed - 50;
    if (seed > 0)
    {
        myFunction(newSeed);
    }
};

Answer 4

I think using objects would be the way to go if you want to do something where you are actually scoping variables.

function myObject(_someNumber) {
    var someNumber = _someNumber;

    this.myFunction = function() {
        this.someNumber -= 10;
        if(this.someNumber > 0)
        {
           this.myFunction(this.someNumber);
        }
    }
}

for(var i=0;i<100;i++)
{
  new myObject().myFunction(someNumber);
}

Answer 5

You want a closure. Well, you might not want it, but it will do what you are asking.

(function() {
    var someNumber=200;
    myFunction=function() {
        someNumber-=10;
        if (someNumber > 0) {
            myFunction();
        }
    }
})();

But properly passing parameters is probably a better idea.