范围似乎不适用于MongoClient.connect

Question

I'm trying to pass a variable into a Mongo query like this:

function retrieveDocNumber( docNumber ) {
    MongoClient.connect( 'mongodb://' + this.mongoUrl + "/" + this.mongoDbName, function(error, db) {
        var lessonCollection = db.collection( 'lessons' );

        if ( error ) {
            console.log( error );
        } else {
            console.log( docNumber ) // Is undefined...
            lessonCollection.findOne( {number: docNumber}, function( error, doc ) {
                console.log( error );
                console.log( doc );
            } );
        }
    });

So I'm not entirely sure what's going on, but the docNumber (and any other variables not directly in the connect functions enclosing scope) are undefined in the connect function. Any workarounds or obvious places where this is going wrong? I need to retrieve a doc from the database using a user defined docNumber.

Answer 1

呃，愚蠢的问题，答案是因为docNumber被错误地解析为字符串而不是整数。