Custom function to check if documents exists in CouchDB nodejs nano

Question

Custom function to check if documents exists in CouchDB nodejs nano

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.

javascript
node.js
express
couchdb

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);
});