Why NPM rocks! - Speaker Deck

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Work sucks go surfing! http://npmjs.org/

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@lmatteis

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What is NPM? NPM is the package manager for the Node JavaScript platform

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It puts modules in place so that node can find them... ...and manages dependency conflicts intelligently

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Imagine you have a project that depends on a module called felix-couchdb

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$ mkdir my-project $ cd my-project $ npm install felix-couchdb Run the npm install command from within your project directory (or any of the parent folders)

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What’s going on behind the scenes $ npm install felix-couchdb ?

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Fetches the package information http://search.npmjs.org/api/felix-couchdb { "_attachments": { "felix-couchdb-1.0.0.tgz": { "content_type": "application/octet-stream", "digest": "md5-uox/epuoVsfQnzTNMW7VqQ==", "length": 13383, "revpos": 3, "stub": true }, "felix-couchdb-1.0.1.tgz": { "content_type": "application/octet-stream", "digest": "md5-ZkipY8lB3rh7/ZSUFrtpiw==", "length": 16937, "revpos": 5, "stub": true }, "felix-couchdb-1.0.2.tgz": { "content_type": "application/octet-stream", "digest": "md5-Z3j31LH/WymAnFFygOf/Qg==", "length": 16813, "revpos": 7, "stub": true } }, "_id": "felix-couchdb", ...

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Registry API http://search.npmjs.org NPM Registry You can search for packages and add your own through a RESTful HTTP JSON API

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HTTP + RESTful = CouchDB Registry API

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NPM creates a ./node_modules directory and puts the felix-couchdb module in it $ ls node_modules $ cd node_modules $ ls felix-couchdb

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Each module contains a package.json file which describes the modules dependencies... and other things

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It reads package.json from within the felix-couchdb directory and downloads the dependencies

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It does the same thing for each of the dependencies down the tree, until there are no more dependencies

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You end up with a structure where everything is local to your working directory! my-project/ node_modules/ felix-couchdb/ node_modules/ request

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If your project is at /home/rick/my-project Node will check these directories for modules: IN ORDER /home/rick/my-project/node_modules /home/rick/node_modules /home/node_modules /node_modules

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Keeps your dependencies structure simple

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my-project/ node_modules/ felix-couchdb/ node_modules/ request

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my-project/ felix-couchdb/ request depends on depends on

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What if two modules have the same dependency?

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./node_modules felix-couchdb /node-xml (v1) ./node_modules /node-xml (v2) My Project jsdom

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