gistfile1.txt

Pipeline events:

* add_product.pre
* add_product.post

Theme could add messages to the pipeline:

ShopifyApi.Pipeline.addProduct(1234, 1).then(function(pipelineStatus, cart) {
 // do things
});

Apps could hook to events:

var priority = 2;
ShopifyApi.Pipeline.listen('add_product.pre', priority, function(requestedId, requestedQuantity) {
 // An app could implement its own logic to prevent the element to be added, for instance
});