How do I get buildFilters always return the function from createMatchFunction

buildFilters.js

/**
 * I want this to always return the promise that resoslves to the result of createMatchFunction(ignore)
 * 
 * this is in a larger file but it's not relevant
 */
function buildFilters(dir, options) {
   
   
   var jpmignorePath = path.join(dir, ".jpmignore");
    //fs is from require('fs-promises')
   return fs.exists(jpmignorePath).then(function (exists){
       //add defaults
       
       //this list is easy to fill so far
       var ignore = [ new MiniMatch('.zip', mmopt), new MiniMatch('.xpi', mmopt)];
       if (options.command != "test")
       {
           ignore.push(new MiniMatch('/tests', mmopt));
       }
       
       
       
       //.jpmignore exists, add filters for every lin in the file
       if (exists)
       {
         //buildJpmFilters returns a promise that resolves with an array of MiniMatch objects
            buildJpmFilters(jpmignorePath).then( function(filters) {
              //combine the list of MiniMatch objects we already have with the new ones
                ignore = ignore.concat(filters)
                //return the function created by createMatchFunction(ignore)
                return createMatchFunction(ignore);
                
            });
            // PROBLEM uh oh, I can't return the then above because I want to just have the function from createMatchFunction
            // like below but here all I have is the promise... how do I return the RESULT of the promise?
       }
       else
       {
         //easy, just return this and I retun a function
           return createMatchFunction(ignore);
       }
   });
    
   
}