My node. js learning path (ii) NPM module management

NPM is a Node package management and distribution tool that has become the unofficial publishing standard for Node modules (packages). With NPM, you can quickly find packages to use for a particular service, download, install, and manage packages that have already been installed.

Common NPM commands There are:

          (1) $NPM install moduleNames
                            Install the Node module
                            Note: if you don't know the name of the module when you use it, you can follow it through the (link: http://search.npmjs.org) website
                                                              The index value finds the desired module. NPM also provides the ability to query   $NPM search indexName
                                                                After the installation, a node_modules directory is generated, which contains the installed node modules.
                                                                Node is installed in both global and local modes. Typically it will run in local mode and the package will be installed
                                                              Go to the local node_modules directory with your application code statistics. In global mode, the Node package will be
                                                              Install to node_modules in the Node installation directory. The global installation command is
                                                              $NPM install -g moduleName. Learn to set the installation mode using $NPM set global=true
                                                          , $NPM get global to view the currently used installation mode.

          (2) $NPM view moduleNames
                                View the package.json folder for the node module
                              Note: if you want to see the contents of a label under the package.json folder, you can use
                                                                $NPM view moduleName labelName

        (3) $NPM list
                              View the node packages installed in the current directory
                              Note: the Node module search starts in the current directory where the code is executed, and the search results depend on the current directory being used
                                                                Node_modules. $NPM list parseable=true can be represented as a directory when
                                                                All previously installed node packages

          (4) $NPM help
                              View help command

        (5) $NPM view moudleName dependencies
                              View package dependencies

        (6) $NPM view moduleName repository. Url
                            View the package's source file address

          (7) $NPM view moduleName engines
                            View the version of Node that the package depends on  

        (8) $NPM help folders
                              View all the folders used by NPM

          (9) $NPM rebuild moduleName
                              Used to rebuild after changing the package content

          (10) $NPM outdated
                                Check if the package is out of date. This command lists all the packages that are out of date so that the package can be updated in a timely manner

          (11) $NPM update moduleName
                                        Update node module

        (12) $NPM uninstall moudleName
                                          Uninstall node module

          (13) an NPM package is a folder containing package.json, which describes the structure of the folder. During his visit to
                                          Ask NPM for the json folder as follows:
                                                      $NPM help json
                                          This command opens a web page by default and may not be typed as a web page if you change the default open program
                                          Open it.

          (14) when releasing an NPM package, you need to verify that a package name already exists
                                      $NPM search packageName

          (15) many times when we are using an NPM package, we often forget the module requiring its interdependence. We can
                                        Use commands such as the following to see which packages the module depends on
 
  NPM is the package manager for node. JS. When developing node. JS, you often use it to install/uninstall packages. In fact, it does the job of distributing the package.

Configuration package. Json

To package the program, you first need to set up the Settings specified by package.json in the root of the program. The contents of package.json must be in strict json format, that is:

Strings should be enclosed in double quotes, not single quotes;
Attribute names must be quoted;
Never add a comma after the last attribute.
There are many properties of the configuration object, you can see here, here is a list of commonly used items:

Name: package name, which cannot be repeated with an existing package.
Version: version number.
Description: a short description.
This is the author information. Contains three attributes: name, email, and url.
Bin: if there are executable files in the program (mainly called from the command line), specify them here. You can specify more than one.
Main: the program entry when the package is called using require.
Dependencies: the version number can be specified.

After configuring package.json, you can first package and install it locally to test whether the program works normally. The installation command is:

NPM install < Local path >

#! The/usr/bin/env node

Without this line, it will open as the system default, rather than running in a node.js environment.

Sign up for an NPM account

To publish the package to NPM, you also need to register an account. NPM does not provide a web version of the registration wizard. Registration is also done from the command line:

NPM adduser
After executing this command, the user name, Email, password will appear in turn, input after waiting for a while.

Release package

With all the preparation in place, execute the following command to publish the package:

NPM publish < Local path >
If you want to update the package, simply change the version number in package.json and re-execute the publish command.