Assuming I have the following in a function:
exports.addnames = function(req, res) {
var names = ["Kelley", "Amy", "Mark"];
for(var i = 0; i < names.length; i++) {
(function (name_now) {
Person.findOne({ name: name_now},
function(err, doc) {
if(!err && !doc) {
var personDoc = new PersonDoc();
personDoc.name = name_now;
console.log(personDoc.name);
personDoc.save(function(err) {});
} else if(!err) {
console.log("Person is in the system");
} else {
console.log("ERROR: " + err);
}
}
);
)(names[i]);
}
My issue is after I save the names, I want to return the results:
Person.find({}, function(err, doc) {
res.json(200, doc);
})
Though I have a callback for names, it appears that the last block of code (Persons.find({})) gets executed before the calls to save all the names is complete... thusly when the user goes to the url in the browser, "doc" is empty... Is there some way I can ensure that the Persons.find({}) is called after the for loop completes?
The easiest way to do things like this is to use an async library like the aptly named async which can be found at https://github.com/caolan/async.
If you have a list of names that you want to save and then return when complete, it would look like:
// save each of the names asynchronously
async.forEach(names, function(name, done) {
Person.findOne({name: name},
function(err, doc) {
// return immediately if there was an error
if(err) return done(err);
// save the person if it doesn't already exist
if(!doc) {
var personDoc = new PersonDoc();
personDoc.name = name;
console.log(personDoc.name);
// the async call is complete after the save completes
return personDoc.save(done);
}
// or if the name is already there, just return successfully
console.log("Person is in the system");
done();
}
);
},
// this function is called after all of the names have been saved
// or as soon as an error occurs
function(err) {
if(err) return console.log('ERROR: ' + err);
Person.find({}, function(err, doc) {
res.json(200, doc);
})
});