Sometimes Data Isn't Being Displayed In Browser

When i click ctr + r sometimes the whole data doesn't show up. on my ('/') page I have a left side and a right side. The left side should display all of the data and the right side

Solution 1:

The simplest but NOT RECOMMENDED way to do what you want would be the code bellow but it usually leads to callback hell or Pyramid of doom and its hard to read so don't use this!!!!

Comp.count({}, function(err, count){
   Comp.find({}).remove({}, function(){
      Comp.create(arr, function(err, docs){
         Comp.find({}, ..., function(err, doc){                
            Comp.findOne().skip(random).exec(function(err, result){
                res.render("index",{})
            })    
         }) 
      })
   })    
})

another way could be to use async.js

async.series([
    function(callback){
        Comp.count({}, function(err, count){
            callback(null, count);
        });
    },
    function(callback){
        Comp.find({}).remove({}, function(){
            callback(null);
        });
    },
    function(callback){
        Comp.create(arr, function(err, docs){
            callback(null);
        });
    },
    function(callback){
        Comp.find({}, ..., function(err, doc){ 
            callback(null);
        });
    },
    function(callback){
        Comp.findOne().skip(random).exec(function(err, lastResult){
            callback(null, lastResult);
        });
    }
],
// optional callback, results is an array of results from each callback if anyfunction(err, results){
    // results is now equal to [count, lastResult]
    res.render("index",{})
});

and finally Promises I haven't tried or used this, so not 100% sure but something like this

var promise = Comp.count({}).exec();

promise.then(function(count) {
    return Comp.find({}).remove({}).exec();
})
.then(function() {
    return Comp.create(arr, ).remove({}).exec();
})
.then(function() {
    return Comp.find({}).remove({}).exec();
})
.then(function() {
    return Comp.find({}).skip(random).exec();
})
.then(function(result) {
    res.render("index",{})
})

Have a look here for some more details about promises on mongoose How to use mongoose Promise - mongo