Merge branch 'add-typescript' into 'master'

Adds typescript support in webpack. With Mike G.

See merge request gitlab-org/gitlab-ce!15264

changelogs/unreleased/add-typescript.yml

+---
+title: Adds typescript support
+merge_request:
+author:
+type: added

config/webpack.config.js

@@ -107,6 +107,10 @@ var config = {
         test: /\.vue$/,
         loader: 'vue-loader',
       },
+      {
+        test: /\.ts$/,
+        loader: 'ts-loader',
+      },
       {
         test: /\.svg$/,
         loader: 'raw-loader',
@@ -252,7 +256,7 @@ var config = {
   ],
 
   resolve: {
-    extensions: ['.js'],
+    extensions: ['.js', '.ts'],
     alias: {
       '~':              path.join(ROOT_PATH, 'app/assets/javascripts'),
       'emojis':         path.join(ROOT_PATH, 'fixtures/emojis'),

package.json

@@ -61,6 +61,8 @@
     "three-orbit-controls": "^82.1.0",
     "three-stl-loader": "^1.0.4",
     "timeago.js": "^2.0.5",
+    "ts-loader": "^3.1.1",
+    "typescript": "^2.6.1",
     "underscore": "^1.8.3",
     "url-loader": "^0.5.8",
     "visibilityjs": "^1.2.4",

tsconfig.json

+{
+  "compilerOptions": {
+    "target": "es5",
+    "strict": true,
+    "module": "es2015",
+    "moduleResolution": "node"
+  }
+}
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