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If a callback calls the enclosing function, would it be called a recursive call?

2 points by anuragpeshne ↗ HN
I asked this question[1] on stackoverflow but could not get any convincing answer:

http.request(options, function(res) { res.on('data', function(chunk) { data+=chunk; });

  res.on('end', function(){
    //do some stuff
    http.request(options, function(res) {...});//is this recursive?
  });
}).end();

Or a simpler case: suppose there is a function which reads a file character by character:

var noOfChar = 10; var i = 0; readChar(function processChar(char){ if(i < noOfChar) { console.log(char); i++; readChar(processChar); //is this recursive? } }

3 comments

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ts-jondin
Edit: Oh, and as for the question itself, no I would not call it a recursive function just because it calls itself; I'd call it a self-referencing function. Where recursive functions are a subset of self-referencing functions.

1. Why does it matter?

2. Your first example I would simply call an asynchronous loop.

3. Your second example could possibly be called single recursion.

4. Recursion should at least consist of a base case and a recursive case, each self-reference should bring the input value closer to the base case which would end the recursion.

(Your second example has a recursive case and falls out into an undefined base case).

5. An example of 4 would be a tree structure where the base case is a leaf and recursion cases are branches.

  function walk (value) {
   if (Array.isArray(value)) {
    value.forEach(walk);
   } else {
    console.log(value);
   }
  }

  walk([[[1, 2, 3, [4, 5, 6]]],[[7, [8, 9, 10], 11, [12]]],13,14]);
would output: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14
anuragpeshne
Thanks, "I would not call it a recursive function just because it calls itself; I'd call it a self-referencing function." - this cleared a lot of things. I'll a write an answer based on this and other things that I read. This will help someone someday.