Node JS, chaining variable number of http requests

Question

I'm using request js library to make HTTP requests to my API. My single API call looks like this:

var options = {
  method: "post",
  url: 'http//example.com',
  json: true,
  headers: headers,
  body: {key: value}
}
request(options, callback);

However, I have array of options, which are needed to be called one after another and I need to break whole chain if one of them fails.

If last chain finishes, I need to output result to console.

I know that chaining callbacks could be fulfilled via promises, but all examples that I have found uses predefined amount of chained requests.

Is it possible?

Answer 1

If you have an array, you can have an index into that array, and have the callback kick off the next request when the previous one finishes. Roughly:

var index = 0;
var options = [/*...array of options objects...*/];
doRequest() {
    request(options[index], function(err, result) {
        // ...handle the result/error here. If there's no error, then:
        if (++index < options.length) {
            // Kick off the next request
            doRequest();
        }
    });
}

While the above can be Promise-ified, since your requestmethod appears not to be, it would just complicate things.