NodeJS请求从函数返回JSON

Question

I've read a couple of posts about this here (callbacks) but I still don't really fully understand how to solve my problem. So I was hoping that somebody here could help me with mine and I would get it better.

Simple put I want the ID I get from the first request to be used for the second request.

I'm new to JavaScript and NodeJS in general.

 function idRequest(name) { var options = { ... }; function callback(error, response, body) { if (response.statusCode == 200 && !error) { const info = JSON.parse(body); //console.log(info.accountId); return info.accountId; } } request(options, callback); } function requestById(accountId) { var options = { ... }; function callback(error, response, body) { if (response.statusCode == 200 && !error) { const info = JSON.parse(body); console.log(info); } } request(options, callback); } var id = idRequest('..'); requestById(id); 

Answer 1

Try by returning a promise from the first function and inside it resolve the callback, so the once it is resolved , you can use it's then to trigger the second function

function idRequest(name) {
  var options = {
    ...
  };

  function callback(error, response, body) {
    if (response.statusCode == 200 && !error) {
      const info = JSON.parse(body);
      //console.log(info.accountId);
      return info.accountId;
    }
  }
  return new Promise(function(resolve, reject) {
    resolve(request(options, callback))

  })
}

function requestById(accountId) {

  var options = {
    ...
  };

  function callback(error, response, body) {
    if (response.statusCode == 200 && !error) {
      const info = JSON.parse(body);
      console.log(info);
    }
  }

  request(options, callback);
}

var id = idRequest('..').then(function(data) {
  requestById(data);
});

Answer 2

since callback is a async call, so var id will be undefined , when you call the requestById(id);

so either you can use the promise method, answered by @brk or you can call your requestById(id) function directly from the first callback.