qddjs / Qdd

qdd is short for quickly download dependencies. That's all it does. It's meant as a replacement for npm ci in situations where you don't need install scripts. (This means no compiled/native-addon modules either.)

This corner is cut in order to deliver modules to you at high speed. See the Benchmarks section below for more details.

This tool, qdd, is not meant as a replacement for npm or even for npm ci. npm is a full-featured JavaScript project management tool, and qdd is not. npm ci isn't a full-featured tool, but still is subject to some overhead in order to maintain levels of compatibility that we're completely ignoring.

All software is about tradeoffs. In this case, we're making the tradeoff that this tool is only useful if all your dependencies are install-script-free. This is a prette severe limitation, but in many situations, this is still good enough to get the job done.

Example

npm i -g qdd
# And now, in a directory with a package-lock.json
qdd

Can I Use It?

To get an idea whether qdd might be appropriate for your project, check that the following are true:

• Your project operates just fine if you pass --ignore-scripts to npm or yarn when you install dependencies.
• You don't rely on bundleDependencies.
• None of your dependencies are from git URLs or other non-registry sources.
• Your operating system is UNIXey (*).

(*) Note: For the moment, Windows is not supported. This will change real soon, I swear!

Usage

In a directory containing a package-lock.json, run qdd on its own to install the dependencies into $PWD/node_modules/. The node_modules directory must not exist prior to running qdd. It will not be deleted automatically, as it would in npm ci.

If the first argument passed to qdd does not start with a -, then the command will be passed through to npm, as found on the $PATH. This is useful for situations where you want to use qdd in place of npm as your project management tool. For example, you can install a single package into your project with qdd install package-name.

Options

Options may either be given as environment variables of the form QDD_OPTION or as command line arguments of the form --option [value]. For boolean values, set the environment variable to 1 or use the command line argument without a value to set the option to true (defualt is false).

• prod|production (boolean): Skip installing devDependencies.
  • Setting the environment variable NODE_ENV=prod or NODE_ENV=production will also turn this on.
• concurrency (number): Number of sockets to download with. (Default 10.)
• debug (boolean): Get some very verbose logging to stderr.
• cache (path string): Location to store the cache. (Default $HOME/.cache/qdd.)
• nocache (boolean): Do not use the disk cache at all.
• onlycache (boolean): Do not install in node_modules, and only use the disk cache.

Experimental Features

Alongside qdd, qdd-node is also installed. This will run your application just as node would, except the loader will check qdd's cache directory. All node options are supported. This works nicely with qdd --onlycache, which skips installing into node_modules. Note that that would not really be necessary because if the cache is missing a package, then qdd --onlycache will be run for you implicitly and then the module will be loaded. To specify the cache directory for qdd-node, set the QDD_CACHE environment variable to absolute path for the cache directory.

To summarize, if your app is qdd-compatible (see "Can I Use It?" section above), then you can simply run it with qdd-node instead of node, and don't bother with the installation step. If your cache is fresh, it will take some time to install the packages into the cache, but otherwise this should be fairly quick.

Since this is an experimental feature, the following limitations apply:

• qdd-node must be run in the same directory as package-lock.json.
• EcmaScript Module loading is not working.

Benchmarks

You can run the benchmarks with npm run bench. This will run both npm ci and qdd, both with primed caches and fresh caches, 10x for each case, and output the averages. You can set the number of iterations with an ITERATIONS environment variable.

On my machine (a Lenovo X1 Carbon from mid 2016), this gives the following output:

 fresh cache npm ci (avg): 7.5899417363 seconds
    fresh cache qdd (avg): 3.9653772702 seconds
primed cache npm ci (avg): 5.4712137427 seconds
   primed cache qdd (avg): 0.4172178746 seconds

It's pretty quick, but remember that speed like this comes with tradeoffs.

Contributing

See CONTRIBUTING.md.

This project uses the Developer's Certificate of Origin. See DCO.txt.

Code of Conduct

See CODE_OF_CONDUCT.md.

License

MIT License. See LICENSE.txt.