unboundedpress/node_modules/package-hash

package-hash

Generates a hash for an installed npm package, useful for salting caches. AVA for example caches precompiled test files. It generates a salt for its cache based on the various packages that are used when compiling the test files.

package-hash can generate an appropriate hash based on the package location (on disk) and the package.json file. This hash is salted with a hash for the package-hash itself.

package-hash can detect when the package-to-be-hashed is a Git repository. In the AVA example this is useful when you're debugging one of the packages used to compile the test files. You can clone it locally and use npm link so AVA can find the clone. The hash will include the HEAD (.git/HEAD) and its corresponding ref (e.g. .git/refs/heads/master), any packed refs (.git/packed-refs), as well as the diff (git diff) for any non-committed changes. This makes it really easy to test your changes without having to explicitly clear the cache in the parent project.

Installation

$ npm install --save package-hash

Usage

const sync = require('package-hash').sync

const hash = sync(require.resolve('babel-core/package.json'))

sync() can be called with a directory or file path. File paths are translated to directories using path.dirname(). The path must exist. A package.json must exist within the directory.

To get the path to an npm package it's best to use require.resolve('the-name/package.json'), since require.resolve('the-name') may resolve to a subdirectory of the package.

You can provide multiple paths:

const hash = sync([
  require.resolve('babel-core/package.json'),
  require.resolve('babel-preset-es2015/package.json')
])

An optional salt value can also be provided:

const hash = sync(require.resolve('babel-core/package.json'), 'salt value')

Currently only a synchronous interface is available.

API

sync(paths, salt?)

paths: string | string[] ➜ can be a single directory or file path, or an array of paths.

salt: Array | Buffer | Object | string ➜ optional. If an Array or Object (not null) it is first converted to a JSON string.

Compatibility

package-hash has been tested with Node 0.10 and above, including Windows support. Note that git diff support is not available in Node 0.10.