Node.js - wait for multiple async calls

Question

I\'m trying to make multiple MongoDB queries before I render a Jade template, but I can\'t quite figure out how to wait until all the Mongo Queries are completed before rend

Answer 1

I'm a big fan of underscore/lodash, so I usually use _.after, which creates a function that only executes after being called a certain number of times.

var finished = _.after(2, doRender);

asyncMethod1(data, function(err){
  //...
  finished();
});

asyncMethod2(data, function(err){
  //...
  finished();
})

function doRender(){
  res.render(); // etc
} 

Since javascript hoists the definition of functions defined with the function funcName() syntax, your code reads naturally: top-to-bottom.