docs(@angular/cli): update documentation for ng new

* for several options that are saved in .angular-cli.json, I've added an explanation of what setting in the json file controls that options.
* added an explanation about what --dry-run will output.
* added possible values for --style option
* added respective documentation in the command
* also added less, sass and styl(stylus) as possible style extensions

The motivation for this change is that sometimes people would want to change some of the settings set by the cli durig ng new, that they might have not known or cared about, for example, prefix.

Author: gioragutt

docs/documentation/new.md

@@ -24,7 +24,7 @@ Default applications are created in a directory of the same name, with an initia
     <code>--dry-run</code> (alias: <code>-d</code>) <em>default value: false</em>
   </p>
   <p>
-    Run through without making any changes.
+    Run through without making any changes. Will list all files that would have been created when running <code>ng new</code>.
   </p>
 </details>
 
@@ -66,6 +66,9 @@ Default applications are created in a directory of the same name, with an initia
   <p>
     The prefix to use for all component selectors.
   </p>
+  <p>
+    You can later change the value in <em>.angular-cli.json</em> (<code>apps[0].prefix</code>).
+  </p>
 </details>
 
 <details>
@@ -129,15 +132,28 @@ Default applications are created in a directory of the same name, with an initia
   <p>
     The name of the source directory.
   </p>
+  <p>
+    You can later change the value in <em>.angular-cli.json</em> (<code>apps[0].root</code>).
+  </p>
 </details>
 
 <details>
   <summary>style</summary>
   <p>
     <code>--style</code> <em>default value: css</em>
   </p>
-  <p>
-    The style file default extension.
+  <div>
+    The style file default extension. Possible values:
+    <ul>
+      <li>css</li>
+      <li>scss</li>
+      <li>less</li>
+      <li>sass</li>
+      <li>styl (<code>stylus</code>)<li>
+    </ul>
+  </div>
+  <p>
+    You can later change the value in <em>.angular-cli.json</em> (<code>defaults.styleExt</code>).
   </p>
 </details>
 

packages/@angular/cli/commands/new.ts

@@ -13,6 +13,8 @@ const Project = require('../ember-cli/lib/models/project');
 const SilentError = require('silent-error');
 const mkdir = denodeify(fs.mkdir);
 
+const configFile = '.angular-cli.json';
+const changeLater = (path: string) => `You can later change the value in "${configFile}" (${path})`;
 
 const NewCommand = Command.extend({
   name: 'new',
@@ -26,7 +28,10 @@ const NewCommand = Command.extend({
       type: Boolean,
       default: false,
       aliases: ['d'],
-      description: 'Run through without making any changes.'
+      description: oneLine`
+        Run through without making any changes.
+        Will list all files that would have been created when running "ng new".
+      `
     },
     {
       name: 'verbose',
@@ -82,20 +87,26 @@ const NewCommand = Command.extend({
       type: String,
       default: 'src',
       aliases: ['sd'],
-      description: 'The name of the source directory.'
+      description: `The name of the source directory. ${changeLater('apps[0].root')}.`
     },
     {
       name: 'style',
       type: String,
       default: 'css',
-      description: 'The style file default extension.'
+      description: oneLine`The style file default extension.
+        Possible values: css, scss, less, sass, styl(stylus).
+        ${changeLater('defaults.styleExt')}.
+      `
     },
     {
       name: 'prefix',
       type: String,
       default: 'app',
       aliases: ['p'],
-      description: 'The prefix to use for all component selectors.'
+      description: oneLine`
+        The prefix to use for all component selectors.
+        ${changeLater('apps[0].prefix')}.
+      `
     },
     {
       name: 'routing',