CODEWITHSUNDEEP
node.jsmongodbmongoose
sudoyum
sudoyum

Reputation: 156

Node JS + Mongoose: saving documents inside while()

I am just playing around with Node and Mongoose and I am curious about the following issue:

I am trying to save documents to mongo from within a loop / interval.

The following works just fine:

setInterval(function(){

    var doc = new myModel({ name: 'test' });

    doc.save(function (err, doc){
        if (err) return console.error(err);
        doc.speak();
    });

}, 1);

The following does not work:

while(true){

    var doc = new myModel({ name: 'test' });

    doc.save(function (err, doc){
        if (err) return console.error(err);
        doc.speak();
    });

}

What is the explanation for this behavior? The save callback is never firing in scenario 2

Additionally, can someone comment on best practices for building "long running workers"? I am interested in using node to build background workers to process queues of data. Is a while() a bad idea? setInterval()? Additionally, I plan to use the forever module to keep the process alive

Thanks!

Upvotes: 0

Views: 167

Answers (1)

JohnnyHK
JohnnyHK

Reputation: 312149

Node.js is single threaded so while(true) will fully occupy the single thread, never giving the doc.save callback a chance to run.

The second part of your question is too broad though, and you should really only ask one question at a time anyway.

Upvotes: 2

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