When comparing Duo vs Yarn, the Slant community recommends Yarn for most people. In the question“What are the best open source front-end package managers?” Yarn is ranked 3rd while Duo is ranked 6th. The most important reason people chose Yarn is:
One of the most important aspects of Yarn is determinism (predictability). The lock file ensures that the same dependencies will always be installed in the same way and order regardless of the machine for a given repository.
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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 The same results will be yielded every time yarn is run in a repository
One of the most important aspects of Yarn is determinism (predictability). The lock file ensures that the same dependencies will always be installed in the same way and order regardless of the machine for a given repository.
Pro Can tell you why a package was installed
yarn why <query>
can tell you why a package was installed and what other packages depend on it.
Pro Good network performance
Yarn efficiently queues up requests and avoids request waterfalls in order to maximize network utilization.
Pro Offline mode
If you've installed a package before, you can install it again without any internet connection.
Pro Flat Mode
Resolve mismatching versions of dependencies to a single version to avoid creating duplicates.
Pro Multiple registries
Install any package from either npm or Bower and keep your package workflow the same.
Pro Network resilience
A single request failing won't cause an install to fail. Requests are retried upon failure.
Pro Good documentation
It looks like it has good documentation.
Pro Security is put at the forefront
Even though it's still in its early stages of development, security is one of the core values on which Yarn is built. It uses checksums to verify the integrity of every package before executing its code. This also helps avoiding errors related to faulty caching or captive portals.
Further steps are also being taken to improve the security of Yarn which will be implemented in the future.
Pro Built by the community for the community
Even though it's backed by Facebook, Yarn is built as a community project first and foremost. It's completely open source and hosted on Github. It's released under a standard open source client and has its own GitHub organization and set up to work under the same governance model that other successful projects have used in the past, such as Rust and Ember.
All of this means that both existing and new contributors will always work together to improve the product and introduce new features while also keeping in mind suggestions coming from the community.
Pro Backed by Facebook and Google
Was created in a collaboration of Facebook with Exponent, Google and Tilde.
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 Takes up disk space
Yarn adds to your disk space usage since it stores dependencies locally.