Javascript recursion within a class

user_6578141 0
Viewed 10789

I am trying to get a recursion method to work in a class context. Within my class I have the following method: 

    countChildren(n, levelWidth, level) {
    if (n.children && n.children.length > 0) {
        if (levelWidth.length <= level + 1) {
            levelWidth.push(0);
        }
        levelWidth[level + 1] += n.children.length;
        n.children.forEach(function (n) {
            this.countChildren(n, levelWidth, level+1);
        });    
    }
    // Return largest openend width
    return levelWidth;
}

However, when I use this method (which worked before when I just used it as function countChildren = ...) it can't... find (?) itself: Cannot read property 'countChildren' of undefined at the recursion.

Does anyone have any ideas?

recursion class javascript
5 Answers

the variable this Gets redefined within:

  1. the inner scope of a for loop
  2. within a inline function declariation
  3. within asynchronous function calls.

I agree with krillgar with the declaration of self. it fixed my problem with an asynchronous call.

obj.prototype.foo = function (string){
   var self = this;
   if(string){ do something }
   else
   setTimeout(function(){
     self.foo("string");
     }, 5000);
}
user_97430210
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