NodeJ，承诺不等待

Question

I have this function that should make 300 requests for a web page (for benchmarking), however the Promise.all is not waiting for those requests to finish before outputting an empty array, any ideas?

function requestLoop(){

  var resultSet= [];

  // options.requests = 300
  // options.url = http://localhost/

  for(var c=1;c<=options.requests; c++){

    http.get(options.url, function(res){

    //  resultSet.push( { request: c, statusCode: res.statusCode});

      resultSet.push(new Promise(function(res){ return { request: c, statusCode: res.statusCode}; }));

    });

  }

  Promise.all(resultSet).then(function(){
    console.log(resultSet);
  });

  return;

}

Promise is bluebird and http is the normal http package

Answer 1

Promise is being pushed in array in callback. Hence By the time Promise.all invokes, array is empty( [] )

Push new Promise in array within loop itself, not in callback

function requestLoop() {
  var resultSet = [];
  for (var c = 1; c <= options.requests; c++) {
    (function(c) {
      resultSet.push(new Promise(function(resolve) {
        http.get(options.url, function(res) {
          resolve({
            request: c,
            statusCode: res.statusCode
          });
        });
      }));
    })(c);
  }
  Promise.all(resultSet).then(function() {
    console.log(resultSet);
  });
}