gistfile1.js

module.exports = function(Model, options) {
    if (!options.rel) throw new Error('Mixin: cascade delete - no relation specified');
    
    var _ = require('lodash');
    var async = require('async');
    
    var beforeDelete = options.before || function(inst, next) {
        process.nextTick(function() { next(null, true); });
    };
    
    var relation = _.find(Model.relations, function(rel) {
        return rel.name === options.rel;
    });
    
    if (!relation) throw new Error('Mixin: cascade delete - relation not found: ' + options.rel);
    if (relation.type === 'referencesMany') throw new Error('Mixin: cascade delete - referencesMany is not supported');
    
    var pk = relation.keyFrom;
    var fk = relation.keyTo;
    
    var TargetModel = relation.modelTo;
    Model.on('deleted', function(id) {
        var filter = { where: {} };
        filter.where[fk] = id;
        var inst = {};
        inst[pk] = id;
        relation.applyScope(inst, filter);
        TargetModel.find(filter, function(err, items) {
            async.map(items || [], function(inst, next) {
                beforeDelete(inst, function(err, del) {
                    if (err || !inst || !del) return next();
                    inst.destroy(function(err) {
                        next(err, inst);
                    });
                });
            }, function(err, results) {
                if (_.isFunction(options.after)) {
                    options.after(err, _.compact(results));
                }
            });
        });
    });
    
};

// models/product.js

module.exports = function(Product, Base) {
    Product.mixin('Cascading', { model: Image });
};

Is this implemented somewhere?