When comparing Duo vs JSPM, the Slant community recommends JSPM for most people. In the question“What are the best open source front-end package managers?” JSPM is ranked 4th while Duo is ranked 6th. The most important reason people chose JSPM is:
JSPM is registry agnostic, it can pull packages from npm and github and is built in such a way it can support more.
Ranked in these QuestionsQuestion Ranking
Pros
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.
Pro Registry agnostic
JSPM is registry agnostic, it can pull packages from npm and github and is built in such a way it can support more.
Pro Module style agnostic
Loads ES6, AMD, CommonJS and globals.
Pro Can transcompile ES6, JSX and Typescript
Pro Much faster than Webpack or Browserify
While Webpack and Browserify recompile the source code using Babel, jspm is the only packager that can load prebuild/minified code downloaded from the npm registry.
Pro Bundled based on imported modules without any config
Create the bundle file without config and add only the modules imported.
Pro Switch between async or sync load
With a simple command you could change between load the modules async by systemjs or sync with a bundle file.
Pro Easy install packages from npm, github or any git repository
Pro Versioned package urls
It creates a packages folders which are versioned. This makes it future proof for a time where we stop bundling all the code. In the following presentation Guy Bedford calls bundling an anti-pattern.
Pro Very easy to start with
Cons
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.
Con You need to be an expert to write shims
You can load any module. But that comes with the price:
you need to find or write configs to load a particular rare module.
Con Doesn't hide complexity
JSPM doesn't try to hide complexity from the user. I.e. when some issue emerges you need understand a lot to be able to patch it or create a workaround.
Con Watcher has bugs
Watching would benefit from improvements
Con Unstable API
0.17 is still in beta. 0.16 is lacking features.
Con Poor bundler performance
Bundling performance is slow, though offset by the fact that bundling is not required during development, since it can load dependencies asynchronously.