title: Why do we need to use package.json?
body: <p>I am trying to learn web socket with JavaScript  to this <a href="http://socket.io/get-started/chat/" rel="nofollow noreferrer">site</a>, but I do not understand something that why I need to use <strong>package.json</strong>. This is my package.json file code:</p>
  
  <pre><code>`{
    "name": "module-name",
    "version": "10.3.1",
    "description": "An example module to illustrate the usage of a package.json",
    "author": "Your Name &lt;you.name@example.org&gt;",
    "contributors": [{
    "name": "Foo Bar",
    "email": "foo.bar@example.com"
  }],
    "bin": {
    "module-name": "./bin/module-name"
  },
    "scripts": {
      "test": "vows --spec --isolate",
      "start": "node index.js",
      "predeploy": "echo im about to deploy",
      "postdeploy": "echo ive deployed",
      "prepublish": "coffee --bare --compile --output lib/foo src/foo/*.coffee"
    },
    "main": "lib/foo.js",
    "repository": {
    "type": "git",
    "url": "https://github.com/nodejitsu/browsenpm.org"
  },
    "bugs": {
    "url": "https://github.com/nodejitsu/browsenpm.org/issues"
  },
    "keywords": [
    "nodejitsu",
    "example",
    "browsenpm"
  ],
    "dependencies": {
      "primus": "*",
      "async": "~0.8.0",
      "express": "4.2.x",
      "winston": "git://github.com/flatiron/winston#master",
      "bigpipe": "bigpipe/pagelet",
      "plates": "https://github.com/flatiron/plates/tarball/master"
    },
    "devDependencies": {
      "vows": "^0.7.0",
      "assume": "&lt;1.0.0 || &gt;=2.3.1 &lt;2.4.5 || &gt;=2.5.2 &lt;3.0.0",
      "pre-commit": "*"
    },
    "preferGlobal": true,
    "private": true,
    "publishConfig": {
    "registry": "https://your-private-hosted-npm.registry.nodejitsu.com"
  },
    "subdomain": "foobar",
    "analyze": true,
    "license": "MIT"
  }` 
  </code></pre>
  
  <p>But I do not understand why I need to use it. I tried to find on google but can not find something useful. One more thing, if I create <code>package.json</code> then why I need to write <strong>dependencies</strong>?</p>