As a Node.js developer, you’ll need several tools in addition to Node.js. This is especially true when you need to develop front-end components.<\/p>\n
These tools are known as packages.<\/p>\n
You use Node Package Manager (NPM)\u00a0 to install and manage this packages in a useful manner. In addition to providing for installation of packages, NPM also provides a useful interface to work with these packages.<\/p>\n
The two thing NPM provides are:<\/p>\n
We would now examine the basics of NPM. I would take you through how to install packages in local and global mode. Also, you will learn how to install, delete and update a package based on version. Then there’s something called package.json which is used to manage dependencies. You’ll learn that too.<\/p>\n
Feel free to watch the video lesson as well if you want.<\/p>\n
<\/p>\n
First, you may have to check if NPM is already installed. To do that, use the command:<\/p>\n
$ npm --version\r\n2.8.1\r\n<\/pre>\n<\/p>\n
If you see the version number as shown above, then node.js is installed. But if not, then you need to install it using the command below:<\/p>\n
$ sudo npm install npm -g\r\n<\/pre>\nAfter installation, you may also have to update it to the latest version. To do that, use the command below.<\/p>\n
sudo npm install npm@latest<\/span> -g\r\n<\/pre>\n<\/p>\n
<\/p>\n
Installing Packages with NPM<\/strong><\/p>\n
To install a module\/package, type the command below, with the name of the module<\/p>\n
$ npm install <Module_Name>\r\n<\/pre>\nFor example, we want to install a module called Uglify (a JavaScript based tool used for minification), you use the command:<\/p>\n
$ npm install uglify-js\r\n<\/pre>\nThen to use this module in your program, you also have to write this code:<\/p>\n
var<\/span> uglify=<\/span> require('uglify-js'<\/span>);\r\n<\/pre>\n<\/p>\n
<\/p>\n
Global and Local Mode<\/strong><\/p>\n
Packages are installed in Local Mode by default. This means that the package is installed in the directory that exists where Node.js is present. The directory is called node_modules. So to use a local package, we must use the require() method.<\/p>\n
Also, you can use the ls command to view all the locally installed modules.<\/p>\n
On the contrary, Global packages are placed in the system directory. They can be used in the command-line interface(CLI) but not importable using the require() function in Node. To install a package in global mode, use the switch –global or -g.<\/p>\n
For example, the previous package can be installed in global mode like this:<\/p>\n
$ npm install uglify-js --global\r\n<\/pre>\nNow, to list the modules available globally, use the command:<\/p>\n
<\/p>\n
$ npm ls -g\r\n<\/pre>\n<\/p>\n
Using package.json<\/strong><\/p>\n
package.json file is used to define the properties of a package. It is available in the root directory of any Node application.<\/p>\n
Exercise<\/strong>: Open a package.json file and view the content<\/p>\n
<\/p>\n
Properties of Package.json<\/strong><\/p>\n
\n
- name<\/b> \u2212 the name of the package<\/li>\n
- version<\/b> \u2212 the version of the package<\/li>\n
- description<\/b> \u2212 the description of the package<\/li>\n
- homepage<\/b> \u2212 the homepage of the package<\/li>\n
- author<\/b> \u2212 the author of the package<\/li>\n
- contributors<\/b> \u2212 the names of the contributors to the package<\/li>\n
- dependencies<\/b> \u2212 a list of dependencies.The dependencies mentioned here are installed by default in the node_module folder of the package.<\/li>\n
- repository<\/b> \u2212 a repository type and URL of the package<\/li>\n
- main<\/b> \u2212 entry point to the package<\/li>\n
- keywords<\/b> \u2212 set of keywords<\/li>\n<\/ul>\n
<\/p>\n
To Uninstall a Module<\/strong>, use the command below:<\/p>\n
$ npm uninstall uglify-js\r\n<\/pre>\nOnce a module is uninstalled, then you can check by examining the content of the node_modules directory using the ls command<\/p>\n
<\/p>\n
To Update a Module:<\/strong><\/p>\n
When a module is updates, the version of the dependencies is upateded to the latest version. The command below updates a module:<\/p>\n
$ npm update uglify-js\r\n<\/pre>\n<\/p>\n
To Search for a Module<\/strong>, use the command:<\/p>\n
$ npm search uglify-js\r\n<\/pre>\n<\/p>\n
Creating a Module<\/strong><\/p>\n
This means that you need to generate a package.json file. This you can also do using NPM. The command below does it<\/p>\n
$ npm init<\/p>\n
Then follow the instructions.<\/p>\n
At the end, you will then execute:<\/p>\n
$ npm publish<\/p>\n
to finally publish the module<\/p>\n","protected":false},"excerpt":{"rendered":"
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