数组中每个值的新API调用

Question

I basically want this kind of object as a result:

[{ id: 5040, requester_id: 1234, requester_name: 'John' }, { id: 5046, requester_id: 999, requester_name: 'Jim' }, { id: 5049, requester_id: 543, requester_name: 'Alex' }]

This is an object of tickets and tickets have multiple properties.

The API I'm using has a call that receives the ticket. No problems retrieving this. The information I get from this API call is this:

[{ id: 5040, requester_id: 1234 }, { id: 5046, requester_id: 999 }, { id: 5049 requester_id: 543 }]

Based on each requester_id I need to do another API call to retreive the name of the requester. For requester_id 1234, it gives me this:

{ requester_id: 1234, name: 'John' }

Each requester requires its own API call to get this information.

If Nodejs were an async programming language, I would do something like this:

 var tickets = api({ method: 'get', path: '/tickets' }); for (var i=0; i<tickets.length; i++){ var contact = api({ method: 'get', path: '/contact/'+tickets[i].requester_id); tickets[i].name = contact.name; } 

Obviously, this doesn't work.

I have tried using callbacks, promises, different tools to get the API data (my preference now is 'request'). I have literally spent 8 hours and I can't get it to work.

I need the for loop to wait until the first API call is finished. Then I need each iteration of the loop to wait for the previous one to finish.

My API function returns a Promise like this:

 return new Promise(function(resolve, reject) { request.get(options, function(err, resp, body) { if (err) { reject(err); } else { resolve(JSON.parse(body)); } }); }); 

Out of many different failed attempts, this is the last one:

 var tickets = []; var contacts = []; var insertContactData = function(reqId){ return api({ method: 'get', path: '/contacts/'+reqId }); } var main = function(){ var myTickets = api({ method: 'get', path: '/tickets'); myTickets.then(function(result) { var ticketData = result.results; for (var i=0; i < result.results.length; i++){ var thisTicket = {}; thisTicket.id = ticketData[i].id; tickets[i] = thisTicket; } var contacts = []; for (var i=0; i < result.results.length; i++){ var idExists = false; for (var j=0; j < contacts.length; j++){ if (contacts[j].requesterId == tickets[i].requesterId){ idExists = true; } } if (idExists == false){ var newCont = {}; newCont.requesterId = tickets[i].requesterId; contacts.push(newCont); } } contacts.shift(); for (var i=0; i < contacts.length; i++){ var pos = i; var reqId = contacts[i].requesterId; var contact = insertContactData(reqId); console.log(contact); } }, errHandler).catch(function(error){ console.log('ERROR '+error); }); } 

Please help?

Answer 1

If you need to wait for an asynchronous request before continuing then you can use async / await

async function loadTicketInfo() { 
  const tickets = await api({ method: 'get', path: '/tickets' });
  for (let i=0; i<tickets.length; i++){
    var contact = await api({ method: 'get', path: '/contact/'+tickets[i].requester_id);
    tickets[i].name = contact.name;
  }
};

Although, depending on how many tickets you expect to pull, this could be a pretty slow operation. I suggest you pull all the ticket information in parallel, and then marry the information up at the end

const ticketInfos = tickets.map(t => api({ method: 'get', path: '/contact/' + t.requester_id));
const infos = await Promise.all(ticketInfos);
tickets.forEach(t => {
  const info = infos.find(i => i.requester_id === t.requester_id);
  if (info) {
    t.requester_name = t.name;
  }
});