Fix the build. Add optional chaining transform. (#2363)

Summary:
#2330 broke the build (_sigh_). CI was broken for a while, so it wasn't immediately obvious too. Internally, we have supported optional chaining for a while, so importing to Phabricator didn't surface the error either.

We need a babel transform for optional chaining.

## Test plan.

Build draft. Build succeeds. Open one of the examples. It works.
Pull Request resolved: #2363

Reviewed By: creedarky

Differential Revision: D20632298

Pulled By: mrkev

fbshipit-source-id: 7a591c376330ee31bac5546a765920833b6bac00

gulpfile.js

@@ -45,7 +45,10 @@ var babelOptsJS = {
       rewriteModules: {map: moduleMap},
     }),
   ],
-  plugins: [require('@babel/plugin-proposal-nullish-coalescing-operator')],
+  plugins: [
+    require('@babel/plugin-proposal-nullish-coalescing-operator'),
+    require('@babel/plugin-proposal-optional-chaining'),
+  ],
 };
 
 var babelOptsFlow = {
@@ -55,7 +58,10 @@ var babelOptsFlow = {
       rewriteModules: {map: moduleMap},
     }),
   ],
-  plugins: [require('@babel/plugin-proposal-nullish-coalescing-operator')],
+  plugins: [
+    require('@babel/plugin-proposal-nullish-coalescing-operator'),
+    require('@babel/plugin-proposal-optional-chaining'),
+  ],
 };
 
 var COPYRIGHT_HEADER = `/**

package.json

@@ -46,7 +46,7 @@
   "devDependencies": {
     "@babel/core": "^7.6.4",
     "@babel/plugin-proposal-nullish-coalescing-operator": "^7.4.4",
-    "@babel/plugin-proposal-optional-chaining": "^7.6.0",
+    "@babel/plugin-proposal-optional-chaining": "^7.9.0",
     "alex": "^8.0.0",
     "babel-eslint": "^10.0.3",
     "babel-preset-fbjs": "^3.3.0",

yarn.lock

@@ -183,6 +183,11 @@
   resolved "https://registry.yarnpkg.com/@babel/helper-plugin-utils/-/helper-plugin-utils-7.0.0.tgz#bbb3fbee98661c569034237cc03967ba99b4f250"
   integrity sha512-CYAOUCARwExnEixLdB6sDm2dIJ/YgEAKDM1MOeMeZu9Ld/bDgVo8aiWrXwcY7OBh+1Ea2uUcVRcxKk0GJvW7QA==
 
+"@babel/helper-plugin-utils@^7.8.0", "@babel/helper-plugin-utils@^7.8.3":
+  version "7.8.3"
+  resolved "https://registry.yarnpkg.com/@babel/helper-plugin-utils/-/helper-plugin-utils-7.8.3.tgz#9ea293be19babc0f52ff8ca88b34c3611b208670"
+  integrity sha512-j+fq49Xds2smCUNYmEHF9kGNkhbet6yVIBp4e6oeQpH1RUs/Ir06xUKzDjDkGcaaokPiTNs2JBWHjaE4csUkZQ==
+
 "@babel/helper-replace-supers@^7.1.0", "@babel/helper-replace-supers@^7.3.4":
   version "7.3.4"
   resolved "https://registry.yarnpkg.com/@babel/helper-replace-supers/-/helper-replace-supers-7.3.4.tgz#a795208e9b911a6eeb08e5891faacf06e7013e13"
@@ -276,13 +281,13 @@
     "@babel/helper-plugin-utils" "^7.0.0"
     "@babel/plugin-syntax-object-rest-spread" "^7.2.0"
 
-"@babel/plugin-proposal-optional-chaining@^7.6.0":
-  version "7.6.0"
-  resolved "https://registry.yarnpkg.com/@babel/plugin-proposal-optional-chaining/-/plugin-proposal-optional-chaining-7.6.0.tgz#e9bf1f9b9ba10c77c033082da75f068389041af8"
-  integrity sha512-kj4gkZ6qUggkprRq3Uh5KP8XnE1MdIO0J7MhdDX8+rAbB6dJ2UrensGIS+0NPZAaaJ1Vr0PN6oLUgXMU1uMcSg==
+"@babel/plugin-proposal-optional-chaining@^7.9.0":
+  version "7.9.0"
+  resolved "https://registry.yarnpkg.com/@babel/plugin-proposal-optional-chaining/-/plugin-proposal-optional-chaining-7.9.0.tgz#31db16b154c39d6b8a645292472b98394c292a58"
+  integrity sha512-NDn5tu3tcv4W30jNhmc2hyD5c56G6cXx4TesJubhxrJeCvuuMpttxr0OnNCqbZGhFjLrg+NIhxxC+BK5F6yS3w==
   dependencies:
-    "@babel/helper-plugin-utils" "^7.0.0"
-    "@babel/plugin-syntax-optional-chaining" "^7.2.0"
+    "@babel/helper-plugin-utils" "^7.8.3"
+    "@babel/plugin-syntax-optional-chaining" "^7.8.0"
 
 "@babel/plugin-syntax-class-properties@^7.0.0":
   version "7.2.0"
@@ -319,12 +324,12 @@
   dependencies:
     "@babel/helper-plugin-utils" "^7.0.0"
 
-"@babel/plugin-syntax-optional-chaining@^7.2.0":
-  version "7.2.0"
-  resolved "https://registry.yarnpkg.com/@babel/plugin-syntax-optional-chaining/-/plugin-syntax-optional-chaining-7.2.0.tgz#a59d6ae8c167e7608eaa443fda9fa8fa6bf21dff"
-  integrity sha512-HtGCtvp5Uq/jH/WNUPkK6b7rufnCPLLlDAFN7cmACoIjaOOiXxUt3SswU5loHqrhtqTsa/WoLQ1OQ1AGuZqaWA==
+"@babel/plugin-syntax-optional-chaining@^7.8.0":
+  version "7.8.3"
+  resolved "https://registry.yarnpkg.com/@babel/plugin-syntax-optional-chaining/-/plugin-syntax-optional-chaining-7.8.3.tgz#4f69c2ab95167e0180cd5336613f8c5788f7d48a"
+  integrity sha512-KoK9ErH1MBlCPxV0VANkXW2/dw4vlbGDrFgz8bmUsBGYkFRcbRwMh6cIJubdPrkxRwuGdtCk0v/wPTKbQgBjkg==
   dependencies:
-    "@babel/helper-plugin-utils" "^7.0.0"
+    "@babel/helper-plugin-utils" "^7.8.0"
 
 "@babel/plugin-transform-arrow-functions@^7.0.0":
   version "7.2.0"