回调函数的范围

Question

I want to implement a function which performs ajax requests (response is json) until there will be no "next" property in response. After that i need to perform some callback function. What is the best way for this? My code below doesn't work because of the wrong callback's scope, and i cannot imagine how to pass it correctly.

_requestPhotos = function(url, callback) {
  getYFContent(url, function(data) {
    // some actions

    if (!!data.next) {
      _requestPhotos(data.next, callback);
    } else {
      callback(smth);
    }
  });
};

Answer 1

There are no obvious errors from the script you've posted. For example, an equivalent test could look like this:

alertResult = function(text) {
   console.log("Result is: " + text);
}

doRecursive = function(data, callback) {
   if(!!data.next) {
      doRecursive(data.next, callback);
   } else {
      callback(data.value);
   }
}

var d = { value: 1, next: { value: 2, next: { value: 3 }}};

doRecursive(d, alertResult);

The log result is "Result is: 3" , which is what you'd expect.

The error is elsewhere. How are you calling this the first time, what is the callback you're passing to it (and how is it defined) and what exactly does getYFContent do?