javascript - 我如何获取javascript服务 Node 中的事件队列

我有一个函数，需要等到解决承诺后再返回值。不幸的是，仅使用while循环并检查是否已解决了诺言，就使线程陷入困境，而不会让我的setTimeout函数执行其回调。我能想到的唯一解决方案是，如果我的d.promise尚未解析为true，则告诉js服务事件队列。贝娄是我的代码：

var _ = require('lodash');
var Q = require('q');

var h = function(x,y,z, callback) {

  setTimeout(function(){
    // This never logs to my terminal
    console.log(x + y + z);
    callback();
  }, 1000);
};

var b = function(x,y,z, callback) {
  console.log(x * y * z);
  callback();
};

chain = function(args, f) {
  var index;
  if( (index = _.indexOf(args,'cb')) < 0 ) {
          f.apply(null,args);
  } else {
      return {
        chain: function(newArgs, fxn) {
          var d = Q.defer();
          args[index] = function() {
            d.resolve(true);
          };
          f.apply(null,args);
          // Don't return until callback is resolved.
          while(d.promise.valueOf() != true){
            // Since the thread is hogged by this loop, I'd like
            // to tell it to manually service my event/function queue
            // so that setTimeout works while this loop polls.

            // This setTimeout will never execute the callback
            setTimeout(function(){console.log('hi');},5);
          };
          return chain(newArgs, fxn);
        }
      }
  }
}

chain([2,2,3,'cb'], h ).
chain([2,5,3, 'cb'], b).
chain([2,1,3,'cb'], h ).
chain([2,2,5, 'cb'], b).
chain([6,6,6, function() {console.log('ok');}], b);

最佳答案

承诺以.then继续类似于常规同步代码以;继续

因此，为了等待诺言解决，您不执行while(promiseNotResolved)而是执行：

promise().then(function(value){
    //code that runs once the promise is resolved
});

关于javascript - 我如何获取javascript服务 Node 中的事件队列，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/23844099/