Introduction to

Introduction to

By Suroor Wijdan

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Agenda● What is NPM?● Understanding package.json● Where to find Packages?● Installing Packages● Writing your own Packages● Command Line● Publishing to NPM● Questions & Exercises

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What is NPM?First Time Using NPM

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What is NPM?● A Node Package Manager● No other Package Manager comes closer● Is also used by developers who don’t use Node.js at all● Created by Isaac Z. Schlueter● Breeze to use● Recently made into a company, NPM Inc. by Isaac● Free and Open Source!

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Understanding package.json● It is a valid JSON object ● name and version fields are required, the combination

makes a unique identifier for the package● Some used fields in package.json

○ description○ keywords○ homepage○ bugs○ license○ author & contributors○ main○ bin○ dependencies○ scripts - {start, preinstall}

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Where to find Packages?

https://npmjs.org

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Installing Packages● npm comes along with node.js● to install a package run:

○ npm install <package-name>○ npm install <tarball file>○ npm install <tarball url>

● install a package globally ○ npm install -g <package-name>

Note: Global installation makes the package available globally irrespective of the directory you installed it from.

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Writing your own packages● Install Grunt , the javascript task runner

○ npm install -g grunt-cli● Run command :

○ grunt-init node● Answer few questions and you are ready with a nice

package.json file and main .js file for your package.

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Writing your own packagesThe generated folder structure should look something like this:

Write the code in the .js file created, you can also create many more files as per your need.

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Writing your own packagesSome guidelines to keep in mind when writing new packages:

● Don’t reinvent the wheel● Try to contribute to other packages whenever possible● If you are writing a utility package, then multiple exports should be used● If your package needs to maintain a state then its good to export a

constructor● Most Important thing, KEEP IT COOL!

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Command LineTo be able to use your package through command line, you need to specify ‘bin’ in package.json as follows:

"bin": {

"nodeart": "lib/nodeArt.js"

}

Also add this #! /usr/bin/env node at the top of “lib/nodeArt.js” file. This tells how the file should be executed.

As above, ‘nodeart’ will be the command available to you when you install the package on your machine.

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Command LineYou can receive the arguments passed from command line in process.argv array. First two values in the array are pre-defined :

[ 'node', '/opt/node-v0.10.5-linux-x64/bin/nodeArt']

The actual arguments being passed will be available at indexes greater than 1. So if you run nodeart ‘suroor wijdan’, the process.argv array will be:

[ 'node', '/opt/node-v0.10.5-linux-x64/bin/nodeArt', ‘suroor wijdan’]

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Command LineSo its better to slice the array and store the arguments in another variable:

var argumentsPassed = process.argv.slice(2);

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Publishing to NPMTo publish on NPM, you just need to have an account on it. To make an account run the following command:

Once you have the account ready, just run the below command from project root to publish your module:

And thats all, everything else will be taken care of by NPM registry.

npm adduser //will ask for username, email and password

npm publish

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Questions?

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/THANKS/ig

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References

1. NPM Logo - https://npmjs.org2. https://npmjs.org/doc/3. Image Credit - http://nodejsreactions.tumblr.com/post/64781824365/first-time-using-npm4. Grunt Logo - http://gruntjs.com