Providing a clear introduction for those starting out.

npm, established in 2010, has long been the go-to package manager for JavaScript developers. To initiate dependency management on your project, simply enter the command:

npm init

This action will create a package.json file housing all of the project's dependencies.

Following that step,

npm install

will establish a directory called node_modules and fetch the specified dependencies (listed in the package.json file).

In addition, it will generate a package-lock.json file outlining the dependency tree that was built. This document allows developers to replicate the exact set of dependencies installed. For instance, one developer might incrementally upgrade a dependency from v2 to v3, while another chooses to jump directly to v3.

While installing dependencies, npm lacks determinism, potentially resulting in distinct node_modules directories between developers and leading to variances in behavior. ** npm faced backlash due to incidents like the one in February 2018 when version 5.7.0 resulted in altering system files if sudo npm was run on Linux.

To address such issues among others, Facebook introduced a new package manager in 2016 called Yarn, a faster, more secure, and reliable option for JavaScript packages.

You can introduce Yarn to your project by executing:

yarn init

This process generates a package.json file. Subsequently, you can install the dependencies with:

yarn install

A directory named node_modules will be created. Alongside this, Yarn will craft a file titled yarn.lock, serving a similar purpose as package-lock.json, yet constructed using a deterministic algorithm for consistent builds.

If you initially began your project with npm, transitioning to Yarn is seamless as it leverages the same package.json. Refer to Migrating from npm for further guidance.

Despite advancements made in each subsequent release of npm, some projects still opt for npm over Yarn.

While @msanford's response covers a lot of ground, one aspect that seems to be missing is the consideration of security vulnerabilities (specifically those listed in OWASP's Known Vulnerabilities).

Yarn

To check for these vulnerabilities in Yarn, you can utilize the command yarn audit. However, it's worth noting that at this point, there isn't a straightforward way to address or fix these issues. This remains an ongoing concern as highlighted on GitHub (https://github.com/yarnpkg/yarn/issues/7075).

npm

In contrast, npm does offer a potential solution through the npm audit fix command, which allows users to address some of the vulnerabilities themselves.

Both npm and Yarn come equipped with their own Continuous Integration tools for managing these audits. These include https://github.com/IBM/audit-ci (tested and proven effective) for npm, and https://yarnpkg.com/package/audit-ci (not personally utilized) for Yarn.

npm:

1. npm is the essential package manager for JavaScript developers, providing a battle-tested command-line interface to the npm ecosystem. It offers flexibility and reliability, trusted by hundreds of thousands of developers worldwide.
2. Unlike Yarn, npm consistently generates a secure lock file without the risk of corruption, eliminating the need for additional tools like yarn-tools for fixes.

Yarn:

1. Yarn introduces a modern package management solution for JavaScript that optimizes download efficiency through caching. With parallelized operations, installation times are faster than ever before, maximizing resource utilization.
2. While NPM supports login with a password, Yarn does not offer this feature.

When you add a package using Yarn (using yarn add packagename), it saves the package locally. This means that in subsequent installs, the package will be used from your disk instead of fetching it from the registry via an HTTP request.

Yarn includes a useful license checker tool, which can come in handy when needing to verify the licenses of all the modules your project relies on.

When working with proprietary software, the choice between npm and Yarn doesn't make much difference. You can utilize npm-shrinkwrap.js with npm or yarn.lock with Yarn.

To learn more, check out this informative blog post:

Thread

Positives::

• Enables features such as simultaneous installation and Zero-Install which leads to improved efficiency

• Enhanced security measures

• Vibrant user community

Negatives::

• Incompatible with older versions of Node.js (below version 5)

• Issues arise when installing native modules

Node Package Manager

Advantages::

• User-friendly interface, particularly beneficial for developers dealing with outdated versions.

• Efficient local package installation to conserve storage space.

Disadvantages::

• Potential security weaknesses still exist

Final Verdict:

Is Thread superior to Node Package Manager?

When it comes to speed and performance, Thread surpasses Node Package Manager due to its parallel installation capability. Thread also offers better security compared to NPM. However, it does consume more disk space than NPM.

Yarn's latest version 4 introduces a convenient command yarn upgrade-interactive, eliminating the need for manual installation of this core plugin. This feature boasts a user-friendly CLI interface that allows you to select the desired update version, including the option to upgrade to a new major version of your dependencies. Unlike npm, Yarn offers this built-in functionality. The closest NPM equivalent is using a third-party package called npm-check-updates, which requires manual installation.

NPM provides the useful npm link command that functions effectively, allowing you to 'install' a local package—typically a library—so it can be tested in another local project where it is being utilized. However, this command may encounter issues or not work properly if attempted in yarn, as noted here.

An additional benefit of using Yarn was its robust workspace management tools, offering capabilities comparable to lerna. However, with the introduction of usable workspace utilities in npm's latest version 8, even npm has enhanced its workspace management features.