feat(files): keep support for legacy .jade files

package.json

@@ -10,6 +10,7 @@
   "main": "lib/index",
   "keywords": [
     "pug",
+    "jade",
     "metalsmith",
     "plugin"
   ],

src/index.js

@@ -13,7 +13,7 @@ export default function ({ locals = {}, filters = {}, useMetadata = false } = {}
     }
 
     Object.keys(files).forEach(function (file) {
-      if (!/\.pug/.test(path.extname(file))) {
+      if (!/\.(pug|jade)/.test(path.extname(file))) {
         return
       }
 

test/fixtures/main/src/legacy.jade

@@ -0,0 +1 @@
+h1 Hello World

test/index.js

@@ -5,7 +5,7 @@ import rimraf from 'rimraf'
 import { test } from 'tap'
 
 test('metalsmith-jade', tap => {
-  tap.plan(8)
+  tap.plan(9)
 
   tap.afterEach(done => rimraf('test/fixtures/*/build', done))
 
@@ -23,6 +23,20 @@ test('metalsmith-jade', tap => {
     })
   })
 
+  tap.test('should support .jade files', assert => {
+    assert.plan(2)
+
+    let smith = new Metalsmith('test/fixtures/main')
+
+    smith.use(pug())
+
+    smith.build(err => {
+      assert.equal(err, null)
+
+      fs.exists('test/fixtures/main/build/legacy.html', exists => assert.ok(exists))
+    })
+  })
+
   tap.test('should pass options to pug', assert => {
     assert.plan(3)