feat: missing pages directory warning (#4054)

## Types of changes
<!--- What types of changes does your code introduce? Put an `x` in all the boxes that apply: -->
- [ ] Bug fix (a non-breaking change which fixes an issue)
- [x] New feature (a non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing functionality to change)


## Description
Resolves #3920 by adding a warning during the build process and a small disclaimer into the default page component.


## Checklist:
- [ ] My change requires a change to the documentation.
- [ ] I have updated the documentation accordingly. (PR: #)
- [x] I have added tests to cover my changes (if not applicable, please state why)
- [x] All new and existing tests are passing.

lib/app/pages/index.vue

@@ -14,6 +14,7 @@
       <a href="https://nuxtjs.org/guide/installation#starting-from-scratch" target="_blank" class="button">
         Get Started
       </a>
+      <p class="Landscape__Page__Explanation">Please create <a href="https://nuxtjs.org/guide/directory-structure#the-pages-directory" target="_blank">the pages directory</a> to suppress this default page.</p>
     </section>
   </div>
 </template>
@@ -66,6 +67,18 @@
       word-spacing: 5px;
   }
 
+  .Landscape__Page__Explanation {
+      font-family: "Quicksand", "Source Sans Pro", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
+      color: #35495e;
+      margin: 16px 0 0;
+      font-size: 16px;
+  }
+
+  .Landscape__Page__Explanation > a {
+      color: #3b8070;
+      text-decoration: underline;
+  }
+
   @media (min-width: 992px) {
     .Landscape__Title {
       font-size: 60px;

lib/builder/builder.js

@@ -133,6 +133,12 @@ export default class Builder {
           )
         } else {
           this._defaultPage = true
+          consola.warn({
+            message: `No \`${this.options.dir.pages}\` directory found in ${dir}.`,
+            additional: 'Using the default built-in page.\n',
+            additionalStyle: 'yellowBright',
+            badge: true
+          })
         }
       }
     }

test/fixtures/missing-pages-dir/missing-pages-dir.test.js

@@ -0,0 +1,17 @@
+import consola from 'consola'
+import { buildFixture } from '../../utils/build'
+
+describe('missing-pages-dir', () => {
+  buildFixture('missing-pages-dir', (builder) => {
+    const options = builder.nuxt.options
+    expect(consola.warn).toHaveBeenCalledTimes(1)
+    expect(consola.warn.mock.calls).toMatchObject([
+      [{
+        message: `No \`${options.dir.pages}\` directory found in ${options.srcDir}.`,
+        additional: 'Using the default built-in page.\n',
+        additionalStyle: 'yellowBright',
+        badge: true
+      }]
+    ])
+  })
+})

test/unit/nuxt.test.js

@@ -40,6 +40,7 @@ describe('nuxt', () => {
 
     const { html } = await nuxt.renderRoute('/')
     expect(html.includes('Universal Vue.js Applications')).toBe(true)
+    expect(/Landscape__Page__Explanation/.test(html)).toBe(true)
 
     await nuxt.close()
   })