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| <h1><a href="../misc/npm-scripts.html">npm-scripts</a></h1> <p>How npm handles the "scripts" field</p> |
| <h2 id="description">DESCRIPTION</h2> |
| <p>npm supports the "scripts" property of the package.json script, for the |
| following scripts:</p> |
| <ul> |
| <li>prepublish: |
| Run BEFORE the package is published. (Also run on local <code>npm |
| install</code> without any arguments.)</li> |
| <li>publish, postpublish: |
| Run AFTER the package is published.</li> |
| <li>preinstall: |
| Run BEFORE the package is installed</li> |
| <li>install, postinstall: |
| Run AFTER the package is installed.</li> |
| <li>preuninstall, uninstall: |
| Run BEFORE the package is uninstalled.</li> |
| <li>postuninstall: |
| Run AFTER the package is uninstalled.</li> |
| <li>preversion, version: |
| Run BEFORE bump the package version.</li> |
| <li>postversion: |
| Run AFTER bump the package version.</li> |
| <li>pretest, test, posttest: |
| Run by the <code>npm test</code> command.</li> |
| <li>prestop, stop, poststop: |
| Run by the <code>npm stop</code> command.</li> |
| <li>prestart, start, poststart: |
| Run by the <code>npm start</code> command.</li> |
| <li>prerestart, restart, postrestart: |
| Run by the <code>npm restart</code> command. Note: <code>npm restart</code> will run the |
| stop and start scripts if no <code>restart</code> script is provided.</li> |
| </ul> |
| <p>Additionally, arbitrary scripts can be executed by running <code>npm |
| run-script <stage></code>. <em>Pre</em> and <em>post</em> commands with matching |
| names will be run for those as well (e.g. <code>premyscript</code>, <code>myscript</code>, |
| <code>postmyscript</code>). Scripts from dependencies can be run with `npm explore</p> |
| <p><pkg> -- npm run <stage>`.</p> |
| <h2 id="common-uses">COMMON USES</h2> |
| <p>If you need to perform operations on your package before it is used, in a way |
| that is not dependent on the operating system or architecture of the |
| target system, use a <code>prepublish</code> script. This includes |
| tasks such as:</p> |
| <ul> |
| <li>Compiling CoffeeScript source code into JavaScript.</li> |
| <li>Creating minified versions of JavaScript source code.</li> |
| <li>Fetching remote resources that your package will use.</li> |
| </ul> |
| <p>The advantage of doing these things at <code>prepublish</code> time is that they can be done once, in a |
| single place, thus reducing complexity and variability. |
| Additionally, this means that:</p> |
| <ul> |
| <li>You can depend on <code>coffee-script</code> as a <code>devDependency</code>, and thus |
| your users don't need to have it installed.</li> |
| <li>You don't need to include minifiers in your package, reducing |
| the size for your users.</li> |
| <li>You don't need to rely on your users having <code>curl</code> or <code>wget</code> or |
| other system tools on the target machines.</li> |
| </ul> |
| <h2 id="default-values">DEFAULT VALUES</h2> |
| <p>npm will default some script values based on package contents.</p> |
| <ul> |
| <li><p><code>"start": "node server.js"</code>:</p> |
| <p>If there is a <code>server.js</code> file in the root of your package, then npm |
| will default the <code>start</code> command to <code>node server.js</code>.</p> |
| </li> |
| <li><p><code>"install": "node-gyp rebuild"</code>:</p> |
| <p>If there is a <code>binding.gyp</code> file in the root of your package and you |
| haven't defined your own <code>install</code> or <code>preinstall</code> scripts, npm will |
| default the <code>install</code> command to compile using node-gyp.</p> |
| </li> |
| </ul> |
| <h2 id="user">USER</h2> |
| <p>If npm was invoked with root privileges, then it will change the uid |
| to the user account or uid specified by the <code>user</code> config, which |
| defaults to <code>nobody</code>. Set the <code>unsafe-perm</code> flag to run scripts with |
| root privileges.</p> |
| <h2 id="environment">ENVIRONMENT</h2> |
| <p>Package scripts run in an environment where many pieces of information |
| are made available regarding the setup of npm and the current state of |
| the process.</p> |
| <h3 id="path">path</h3> |
| <p>If you depend on modules that define executable scripts, like test |
| suites, then those executables will be added to the <code>PATH</code> for |
| executing the scripts. So, if your package.json has this:</p> |
| <pre><code>{ "name" : "foo" |
| , "dependencies" : { "bar" : "0.1.x" } |
| , "scripts": { "start" : "bar ./test" } } |
| </code></pre><p>then you could run <code>npm start</code> to execute the <code>bar</code> script, which is |
| exported into the <code>node_modules/.bin</code> directory on <code>npm install</code>.</p> |
| <h3 id="package-json-vars">package.json vars</h3> |
| <p>The package.json fields are tacked onto the <code>npm_package_</code> prefix. So, |
| for instance, if you had <code>{"name":"foo", "version":"1.2.5"}</code> in your |
| package.json file, then your package scripts would have the |
| <code>npm_package_name</code> environment variable set to "foo", and the |
| <code>npm_package_version</code> set to "1.2.5"</p> |
| <h3 id="configuration">configuration</h3> |
| <p>Configuration parameters are put in the environment with the |
| <code>npm_config_</code> prefix. For instance, you can view the effective <code>root</code> |
| config by checking the <code>npm_config_root</code> environment variable.</p> |
| <h3 id="special-package-json-config-object">Special: package.json "config" object</h3> |
| <p>The package.json "config" keys are overwritten in the environment if |
| there is a config param of <code><name>[@<version>]:<key></code>. For example, |
| if the package.json has this:</p> |
| <pre><code>{ "name" : "foo" |
| , "config" : { "port" : "8080" } |
| , "scripts" : { "start" : "node server.js" } } |
| </code></pre><p>and the server.js is this:</p> |
| <pre><code>http.createServer(...).listen(process.env.npm_package_config_port) |
| </code></pre><p>then the user could change the behavior by doing:</p> |
| <pre><code>npm config set foo:port 80 |
| </code></pre><h3 id="current-lifecycle-event">current lifecycle event</h3> |
| <p>Lastly, the <code>npm_lifecycle_event</code> environment variable is set to |
| whichever stage of the cycle is being executed. So, you could have a |
| single script used for different parts of the process which switches |
| based on what's currently happening.</p> |
| <p>Objects are flattened following this format, so if you had |
| <code>{"scripts":{"install":"foo.js"}}</code> in your package.json, then you'd |
| see this in the script:</p> |
| <pre><code>process.env.npm_package_scripts_install === "foo.js" |
| </code></pre><h2 id="examples">EXAMPLES</h2> |
| <p>For example, if your package.json contains this:</p> |
| <pre><code>{ "scripts" : |
| { "install" : "scripts/install.js" |
| , "postinstall" : "scripts/install.js" |
| , "uninstall" : "scripts/uninstall.js" |
| } |
| } |
| </code></pre><p>then <code>scripts/install.js</code> will be called for the install |
| and post-install stages of the lifecycle, and <code>scripts/uninstall.js</code> |
| will be called when the package is uninstalled. Since |
| <code>scripts/install.js</code> is running for two different phases, it would |
| be wise in this case to look at the <code>npm_lifecycle_event</code> environment |
| variable.</p> |
| <p>If you want to run a make command, you can do so. This works just |
| fine:</p> |
| <pre><code>{ "scripts" : |
| { "preinstall" : "./configure" |
| , "install" : "make && make install" |
| , "test" : "make test" |
| } |
| } |
| </code></pre><h2 id="exiting">EXITING</h2> |
| <p>Scripts are run by passing the line as a script argument to <code>sh</code>.</p> |
| <p>If the script exits with a code other than 0, then this will abort the |
| process.</p> |
| <p>Note that these script files don't have to be nodejs or even |
| javascript programs. They just have to be some kind of executable |
| file.</p> |
| <h2 id="hook-scripts">HOOK SCRIPTS</h2> |
| <p>If you want to run a specific script at a specific lifecycle event for |
| ALL packages, then you can use a hook script.</p> |
| <p>Place an executable file at <code>node_modules/.hooks/{eventname}</code>, and |
| it'll get run for all packages when they are going through that point |
| in the package lifecycle for any packages installed in that root.</p> |
| <p>Hook scripts are run exactly the same way as package.json scripts. |
| That is, they are in a separate child process, with the env described |
| above.</p> |
| <h2 id="best-practices">BEST PRACTICES</h2> |
| <ul> |
| <li>Don't exit with a non-zero error code unless you <em>really</em> mean it. |
| Except for uninstall scripts, this will cause the npm action to |
| fail, and potentially be rolled back. If the failure is minor or |
| only will prevent some optional features, then it's better to just |
| print a warning and exit successfully.</li> |
| <li>Try not to use scripts to do what npm can do for you. Read through |
| <code><a href="../files/package.json.html">package.json(5)</a></code> to see all the things that you can specify and enable |
| by simply describing your package appropriately. In general, this |
| will lead to a more robust and consistent state.</li> |
| <li>Inspect the env to determine where to put things. For instance, if |
| the <code>npm_config_binroot</code> environment variable is set to <code>/home/user/bin</code>, then |
| don't try to install executables into <code>/usr/local/bin</code>. The user |
| probably set it up that way for a reason.</li> |
| <li>Don't prefix your script commands with "sudo". If root permissions |
| are required for some reason, then it'll fail with that error, and |
| the user will sudo the npm command in question.</li> |
| <li>Don't use <code>install</code>. Use a <code>.gyp</code> file for compilation, and <code>prepublish</code> |
| for anything else. You should almost never have to explicitly set a |
| preinstall or install script. If you are doing this, please consider if |
| there is another option. The only valid use of <code>install</code> or <code>preinstall</code> |
| scripts is for compilation which must be done on the target architecture.</li> |
| </ul> |
| <h2 id="see-also">SEE ALSO</h2> |
| <ul> |
| <li><a href="../cli/npm-run-script.html">npm-run-script(1)</a></li> |
| <li><a href="../files/package.json.html">package.json(5)</a></li> |
| <li><a href="../misc/npm-developers.html">npm-developers(7)</a></li> |
| <li><a href="../cli/npm-install.html">npm-install(1)</a></li> |
| </ul> |
| |
| </div> |
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| </table> |
| <p id="footer">npm-scripts — npm@2.15.8</p> |
| |