--- /dev/null
+npm-shrinkwrap(1) -- Lock down dependency versions
+=====================================================
+
+## SYNOPSIS
+
+ npm shrinkwrap
+
+## DESCRIPTION
+
+This command locks down the versions of a package's dependencies so
+that you can control exactly which versions of each dependency will be
+used when your package is installed. The `package.json` file is still
+required if you want to use `npm install`.
+
+By default, `npm install` recursively installs the target's
+dependencies (as specified in `package.json`), choosing the latest
+available version that satisfies the dependency's semver pattern. In
+some situations, particularly when shipping software where each change
+is tightly managed, it's desirable to fully specify each version of
+each dependency recursively so that subsequent builds and deploys do
+not inadvertently pick up newer versions of a dependency that satisfy
+the semver pattern. Specifying specific semver patterns in each
+dependency's `package.json` would facilitate this, but that's not always
+possible or desirable, as when another author owns the npm package.
+It's also possible to check dependencies directly into source control,
+but that may be undesirable for other reasons.
+
+As an example, consider package A:
+
+ {
+ "name": "A",
+ "version": "0.1.0",
+ "dependencies": {
+ "B": "<0.1.0"
+ }
+ }
+
+package B:
+
+ {
+ "name": "B",
+ "version": "0.0.1",
+ "dependencies": {
+ "C": "<0.1.0"
+ }
+ }
+
+and package C:
+
+ {
+ "name": "C",
+ "version": "0.0.1"
+ }
+
+If these are the only versions of A, B, and C available in the
+registry, then a normal `npm install A` will install:
+
+ A@0.1.0
+ `-- B@0.0.1
+ `-- C@0.0.1
+
+However, if B@0.0.2 is published, then a fresh `npm install A` will
+install:
+
+ A@0.1.0
+ `-- B@0.0.2
+ `-- C@0.0.1
+
+assuming the new version did not modify B's dependencies. Of course,
+the new version of B could include a new version of C and any number
+of new dependencies. If such changes are undesirable, the author of A
+could specify a dependency on B@0.0.1. However, if A's author and B's
+author are not the same person, there's no way for A's author to say
+that he or she does not want to pull in newly published versions of C
+when B hasn't changed at all.
+
+In this case, A's author can run
+
+ npm shrinkwrap
+
+This generates `npm-shrinkwrap.json`, which will look something like this:
+
+ {
+ "name": "A",
+ "version": "0.1.0",
+ "dependencies": {
+ "B": {
+ "version": "0.0.1",
+ "from": "B@^0.0.1",
+ "resolved": "https://registry.npmjs.org/B/-/B-0.0.1.tgz",
+ "dependencies": {
+ "C": {
+ "version": "0.0.1",
+ "from": "org/C#v0.0.1",
+ "resolved": "git://github.com/org/C.git#5c380ae319fc4efe9e7f2d9c78b0faa588fd99b4"
+ }
+ }
+ }
+ }
+ }
+
+The shrinkwrap command has locked down the dependencies based on
+what's currently installed in node_modules. When `npm install`
+installs a package with an `npm-shrinkwrap.json` in the package
+root, the shrinkwrap file (rather than `package.json` files) completely
+drives the installation of that package and all of its dependencies
+(recursively). So now the author publishes A@0.1.0, and subsequent
+installs of this package will use B@0.0.1 and C@0.0.1, regardless the
+dependencies and versions listed in A's, B's, and C's `package.json`
+files.
+
+
+### Using shrinkwrapped packages
+
+Using a shrinkwrapped package is no different than using any other
+package: you can `npm install` it by hand, or add a dependency to your
+`package.json` file and `npm install` it.
+
+### Building shrinkwrapped packages
+
+To shrinkwrap an existing package:
+
+1. Run `npm install` in the package root to install the current
+ versions of all dependencies.
+2. Validate that the package works as expected with these versions.
+3. Run `npm shrinkwrap`, add `npm-shrinkwrap.json` to git, and publish
+ your package.
+
+To add or update a dependency in a shrinkwrapped package:
+
+1. Run `npm install` in the package root to install the current
+ versions of all dependencies.
+2. Add or update dependencies. `npm install` each new or updated
+ package individually and then update `package.json`. Note that they
+ must be explicitly named in order to be installed: running `npm
+ install` with no arguments will merely reproduce the existing
+ shrinkwrap.
+3. Validate that the package works as expected with the new
+ dependencies.
+4. Run `npm shrinkwrap`, commit the new `npm-shrinkwrap.json`, and
+ publish your package.
+
+You can use npm-outdated(1) to view dependencies with newer versions
+available.
+
+### Other Notes
+
+A shrinkwrap file must be consistent with the package's `package.json`
+file. `npm shrinkwrap` will fail if required dependencies are not
+already installed, since that would result in a shrinkwrap that
+wouldn't actually work. Similarly, the command will fail if there are
+extraneous packages (not referenced by `package.json`), since that would
+indicate that `package.json` is not correct.
+
+Since `npm shrinkwrap` is intended to lock down your dependencies for
+production use, `devDependencies` will not be included unless you
+explicitly set the `--dev` flag when you run `npm shrinkwrap`. If
+installed `devDependencies` are excluded, then npm will print a
+warning. If you want them to be installed with your module by
+default, please consider adding them to `dependencies` instead.
+
+If shrinkwrapped package A depends on shrinkwrapped package B, B's
+shrinkwrap will not be used as part of the installation of A. However,
+because A's shrinkwrap is constructed from a valid installation of B
+and recursively specifies all dependencies, the contents of B's
+shrinkwrap will implicitly be included in A's shrinkwrap.
+
+### Caveats
+
+If you wish to lock down the specific bytes included in a package, for
+example to have 100% confidence in being able to reproduce a
+deployment or build, then you ought to check your dependencies into
+source control, or pursue some other mechanism that can verify
+contents rather than versions.
+
+## SEE ALSO
+
+* npm-install(1)
+* package.json(5)
+* npm-ls(1)
Code Review / simantics / district.git / blobdiff