CODEWITHSUNDEEP
javascriptnode.jsmongoose
brucelee
brucelee

Reputation: 147

NOT doesn't work in node/mongoose

I basically just want to toggle something between true and false.

var currentvalue = doc.findOne({ _id : req.params.the_id });
var opposite = !currentvalue.somethingTrue;
console.log("will this work?? " + opposite);
doc.update({ _id : req.params.the_id }, { $set : { somethingTrue : opposite }})

the console always logs true. it just doesn't work. in the world of node and mongoose, should I do this different?

Also, is it possible now to just enter an expression in mongodb/mongoose, instead of having a workaround like this?(which doesn't even work :/ )

Upvotes: 0

Views: 27

Answers (1)

Jonathan Lonowski
Jonathan Lonowski

Reputation: 123513

The value of opposite will always be true because currentvalue.somethingTrue will always be undefined, which is a "falsy" value in JavaScript:

console.log( currentvalue.somethingTrue );  // undefined
console.log( !currentvalue.somethingTrue ); // true

And, it's undefined because the object returned from .findOne() is a Query instance rather than the document being retrieved from the database.

.findOne() also acts asynchronously (without blocking surrounding code from continuing), so for it to provide the document, it expects a callback function that it can invoke when the document has become available (or an err has occurred):

doc.findOne({ _id : req.params.the_id }, function (err, currentvalue) {
    var opposite = !currentvalue.somethingTrue;
    // etc.
});

Upvotes: 1

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