函数正在调用自身，而没有在其中实现任何递归调用

我有这个函数从mongodb DB获取商店。

exports.find_shops = function(selector, fields, limit, skip, cb){
    if(typeof fields == 'function'){
        limit = 0
        cb = fields
        fields = {}
        skip = 0
    }
    if(typeof limit == 'function'){
        cb = limit
        limit = 0
        skip = 0
    }
    if(typeof skip == 'function'){
        cb = skip
        skip = 0
    }
    if(typeof selector == 'string'){
        limit = 1
        selector = {_id: new db.bson_serializer.ObjectID(selector)}
    }
    console.log('a')
    Shop.find(selector, fields).limit(limit).toArray(function(err, shops){
        console.log('b')
        if(err){
            throw new Error(err)
        } else {
            if(limit == 1){
                cb(shops[0])
            } else {
                cb(shops)
            }
        }
    })
}

bb

而我希望它是

b

怎么了?

exports.search = function(products, location, skip, cb){
    if(typeof skip == 'function'){
        cb = skip
        skip = 0
    }
    this.find_shops({
        products: {
            $in: products
        },
        $or: [{
            location: { $near: location , $maxDistance: 2 }
        },
        {
            delivery: -1
        },
        {
            delivery: {$lt: 2}
        }]
        }, {name: 1, location: 1, delivery: 1, products: 1}, 10, skip, function(shops){
            shops.forEach(function(i,shop){
                shops[i] = _.intersect(shop.products, products)
            })
            // now we have the products that user needs from this shop.
            var combos = []
            shops.forEach(function(i,shop1){
                var combo = [i]
                var p = shop1.products
                shops.forEach(function(j,shop2){
                    if(i > j){
                        return
                    } else {
                        var newprod = _.intersect(p,shop2.products)
                        if(newprod.length == shop2.products.length){
                            return
                        } else {
                            p.push(shop2.products)
                            p = _.uniq
                            combo.push(j)
                            if(p.length == products.length){
                                combos.push(combo)
                            }
                        }
                    }
                })
            })
            cb(combos)
        })
}