Refactor CLI and add tests

src/cli/index.js

@@ -0,0 +1,48 @@
+var updateNotifier = require('update-notifier')
+var yargs = require('yargs')
+var run = require('./run')
+var pkg = require('../../package.json')
+
+module.exports = function () {
+
+  updateNotifier({ pkg: pkg }).notify()
+
+  var argv = yargs
+    .usage('$0 [options] <source>')
+    .options({
+      port: {
+        alias: 'p',
+        description: 'Set port',
+        default: 3000
+      },
+      host: {
+        alias: 'H',
+        description: 'Set host',
+        default: '0.0.0.0'
+      },
+      watch: {
+        alias: 'w',
+        description: 'Watch file(s)'
+      },
+      routes: {
+        alias: 'r',
+        description: 'Load routes file'
+      },
+      id: {
+        description: 'Set database id property (e.g. _id)',
+        default: 'id'
+      }
+    })
+    .boolean('watch')
+    .help('help').alias('help', 'h')
+    .version(pkg.version).alias('version', 'v')
+    .example('$0 db.json', '')
+    .example('$0 file.js', '')
+    .example('$0 http://example.com/db.json', '')
+    .epilog('https://github.com/typicode/json-server')
+    .require(1, 'Missing <source> argument')
+    .argv
+
+  run(argv)
+
+}