node.js - Mongoose find use result in the main code -

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var mongoose = require('mongoose');  var result = false;  thecollecton.findone({name: "hey"}, function(err,obj) {      if(err) console.log(err);     if(obj) result=true; });   console.log(result);  // other things result

and... doesn't work (and know why). how can make works ?

it doesn't work because findone() call asynchronous. when call console.log(), execution of findone() not finished yet. need call console.log() inside asynchronous function:

var mongoose = require('mongoose');  var result = false;  thecollecton.findone({name: "hey"}, function(err,obj) {      if(err) console.log(err);     if(obj) result=true;     console.log(result); });

edit: replying comment. if query in function , want use result of query in caller, need pass callback function. this, need modify function accept callback, example:

function exists(name, callback) {   thecollecton.findone({name: name}, function(err,obj) {     var result = (err || !obj) ? false : true;     callback(result);   }); }

and call function callback:

exists('hey', function(result) {   if (result) {     // something.   } });

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