When comparing Jam vs Duo, the Slant community recommends Duo for most people. In the question“What are the best open source front-end package managers?” Duo is ranked 6th while Jam is ranked 8th. The most important reason people chose Duo is:
Because Duo allows you to require dependencies directly in your html, css, and javascript, you don't need to manage annoying build processes. Duo automatically supports preprocessed languages like Coffeescript and Sass, and automatically bundles them into a single file, making it an easy-to-use, all-in-one tool. All you have to do is run `duo in > out` and you're done!
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Pros
Pro Has a central package repository
A central repository provides more guarantees about the availability of the package. With requiring directly from repository urls, the entire project could potentially be taken down on a whim.
Pro Community is focused on client side javascript
Because Jam only manages Javascript and only works on the client side, you have the assurance that any packages listed are AMD compatible for asynchronous loading.
Pro Architecture independent
Jam's only a front-end package manager, the rest of your server can be on a different architecture or framework. No matter what the architecture, Jam will integrate easily with it.
Pro Provides the best AMD compatibility allowing for better asynchronous loading
Jam requires AMD (Asynchronous Module Definition), which means faster package loading, as it can be done asynchronously.
Pro Handles the entire build and packaging process for you
Because Duo allows you to require dependencies directly in your html, css, and javascript, you don't need to manage annoying build processes. Duo automatically supports preprocessed languages like Coffeescript and Sass, and automatically bundles them into a single file, making it an easy-to-use, all-in-one tool. All you have to do is run duo in > out
and you're done!
Pro Allows you to directly require dependencies from Javascript, HTML, and CSS
With Duo you don't need to manage a separate dependency file, you just require projects from your files where you need them. It works with all front-end languages, giving you powerful inline Javascript, HTML, CSS, and even JSON management in a way that no other package manager supports.
Pro Require directly from github
Duo allows you to use require
to import packages directly from github using the username/package_name@version
syntax. The version is optional, in case you want to test out a new package quickly.
Pro Built on top of Component
Duo can be seen as an easier to use, more feature complete wrapper around component.
Pro Supports both Bower and Component packages
Duo is primarily designed to support Component packages, but Bower package support is available with npm support planned, so you can use Duo with libraries as well as components.
Cons
Con Forced AMD compatibility means fewer libraries
AMD is currently not as popular as CommonJS modules, which means if a library isn't supported, you'll have to deal with it yourself.
Con Harder to manage versions between files
Because versions and dependencies can be specified inline, it might be harder to update your packages when you want to upgrade. (However, it is possible to specify dependencies in a JSON file.)
Con Cannot extract modules from a bundle and put into another one
As for common modules shared by multiple pages, duo.js cannot extract and put them into another bundle which is loaded commonly. On the other hand, modules modified rarely should put into another bundle so they can be still cached when other modules change.