Custom function to check if documents exists in CouchDB nodejs nano

Question

I've been looking for an answer on Google, and based on the results found, I am able to check whether a table exists or not in CouchDB, using nano module.

However, when I try to make it a custom function, it always return "undefined" no matter what. Here is the function:

var exists = function( id ) {

    this.head( id, function( err, body, header ) {

        if ( header[ 'status-code' ] == 200 )
            return true;
        else if ( err[ 'status-code' ] == 404 )
            return false;

        return false;

    });

}

Call it:

nano.db.create( 'databaseName', function() {

    var users = nano.use( 'databaseName' );

    console.log( exists.call( users, 'documentToCheck' ) );

});

What exactly was wrong here? I can't seem to figure it out correctly.

Answer 1

Your function exists returns undefined, because inner anonymous function returns your needed value.

Cure for this disease is to refector your function exists

var exists = function( id , cb) {

    this.head( id, function( err, body, header ) {

        if ( header[ 'status-code' ] == 200 )
            cb(true);
        else if ( err[ 'status-code' ] == 404 )
            cb(false);

        cb(false);

    });

}

Usage:

exists.call(users, 'documentToCheck', function(check) {
    console.log(check);
});