[mquandalle]

This looks to be a great declarative/reactive template engine. I've been working mostly with the Meteor Blaze template engine the last few months. Both of them use a "normal" template language for writing views and (potentially) let you choose if you prefer writing your templates in Handlebars, Jade, or Haml [0], which I find far more easy to use than React JSX format. I think Blaze beats Hamlet on the runtime rendering engine.

First, Blaze does not require to set a root element in a template, which could be a source of bugs with Hamlet because for instance the `each` child is a template, here is a snippet of problematic example from the Hamlet README:

  - each @items, ->
    .first
    .second

This works perfectly fine in Blaze. IIRC Blaze uses comments node on the DOM that are never rendered in browsers in order to define some "domrange" that keep track of n children in a single parent group.

The second runtime issue in Hamlet appears when a third-party library directly modifies the DOM, without telling the template engine. Basically the modification will be erased on the next template redraw which make this system incompatible with all jQuery plugins for instance. Blaze has "fined grained DOM updates" which mean that the modification of a single element in a template does not require to touch any other node in the DOM. For instance if you have a each loop of inputs, and the user start to enter some data in one input field, and for some reason the template is redrawn the text will stay in the input with Blaze, but will be erased with Hamlet.

Blaze also support reactive SVG (I'm not sure if Hamlet supports it but I haven't seen any particular mention in the code).

I think all of these features can be implemented in Hamlet drawing on Blaze and ReactJS runtimes.

Nevertheless I find the Javascript model declaration cleaner in Hamlet than in Blaze or Backbone or React. The only thing I'm not sure about is writing the js events in the template and not in the model, I actually like having all events of a given template in a single place but I don't have strong opinion on this.

[0]: Meteor support Spacebars (which is quite similar to Handlebars) by default https://github.com/meteor/meteor/blob/devel/packages/spaceba..., and there is also a package for jade https://github.com/mquandalle/meteor-jade (disclaimer: I'm the author). It also seems that it wouldn't be difficult to support other languages than Haml for Hamlet.

[Yahivin]

That issue about requiring a root item should be solvable in the future, it's just the current implementation that has limitations. I'm building up the test suite to specify the behavior and hope to have it working soon.

For the most part jQuery plugins should work fine with Hamlet, so long as one remembers to update the data in the model rather than arbitrarily throughout the DOM. It can be a moderate mental shift to go from jQuery style "The DOM is the data" to the newer Backbone, Knockout, React, Angular, etc style of "The model is the data" and may not be right for all applications.

Thanks for the comment I'll take a look at Meteor Blaze and see what cool tricks it has :)

[mquandalle]

The problem is that most current jQuery plugins modify the DOM. If someone want to use a jQuery carousel, the plugin will add arrows buttons and page indicators in the DOM. Then if the template engine updates one of the carousel slide, these nodes will be removed and the plugin will be broken.

[Yahivin]

My advice for that kind of application would be to have a piecemeal approach. Use Hamlet for some templates on your page, and jQuery plugins for others. I hope it's modular enough to use as little or as much as you like.