Enable null coalescing operator

Summary: Enable using the `??` operator in plugin code

Reviewed By: passy

Differential Revision: D18906291

fbshipit-source-id: b0a9b29ebb2896ede10540ba2e4cfd937fb99c7d

static/package.json

@@ -8,6 +8,7 @@
     "@babel/generator": "^7.7.2",
     "@babel/parser": "^7.7.3",
     "@babel/plugin-proposal-class-properties": "^7.7.0",
+    "@babel/plugin-proposal-nullish-coalescing-operator": "^7.7.4",
     "@babel/plugin-proposal-object-rest-spread": "^7.6.2",
     "@babel/plugin-proposal-optional-chaining": "^7.6.0",
     "@babel/plugin-transform-flow-strip-types": "^7.6.3",
@@ -24,7 +25,6 @@
     "xdg-basedir": "^4.0.0",
     "yargs": "^15.0.1"
   },
-  "devDependencies": {},
   "resolutions": {
     "metro/temp": "0.9.0",
     "ws": "7.2.0"

static/transforms/index.js

@@ -22,13 +22,20 @@ function transform({filename, options, src}) {
   let ast = babylon.parse(src, {
     filename,
     plugins: isTypeScript
-      ? ['jsx', 'typescript', 'classProperties', 'optionalChaining']
+      ? [
+          'jsx',
+          'typescript',
+          'classProperties',
+          'optionalChaining',
+          'nullishCoalescingOperator',
+        ]
       : [
           'jsx',
           ['flow', {all: true}],
           'classProperties',
           'objectRestSpread',
           'optionalChaining',
+          'nullishCoalescingOperator',
         ],
     sourceType: 'module',
   });
@@ -43,6 +50,7 @@ function transform({filename, options, src}) {
       require('../node_modules/@babel/plugin-proposal-class-properties'),
       require('../node_modules/@babel/plugin-transform-flow-strip-types'),
       require('../node_modules/@babel/plugin-proposal-optional-chaining'),
+      require('../node_modules/@babel/plugin-proposal-nullish-coalescing-operator'),
       require('./dynamic-requires.js'),
     );
   } else {
@@ -51,6 +59,7 @@ function transform({filename, options, src}) {
       require('../node_modules/@babel/plugin-proposal-class-properties'),
       require('../node_modules/@babel/plugin-transform-modules-commonjs'),
       require('../node_modules/@babel/plugin-proposal-optional-chaining'),
+      require('../node_modules/@babel/plugin-proposal-nullish-coalescing-operator'),
     );
   }
 

static/yarn.lock

@@ -415,6 +415,14 @@
     "@babel/helper-plugin-utils" "^7.0.0"
     "@babel/plugin-syntax-nullish-coalescing-operator" "^7.2.0"
 
+"@babel/plugin-proposal-nullish-coalescing-operator@^7.7.4":
+  version "7.7.4"
+  resolved "https://registry.yarnpkg.com/@babel/plugin-proposal-nullish-coalescing-operator/-/plugin-proposal-nullish-coalescing-operator-7.7.4.tgz#7db302c83bc30caa89e38fee935635ef6bd11c28"
+  integrity sha512-TbYHmr1Gl1UC7Vo2HVuj/Naci5BEGNZ0AJhzqD2Vpr6QPFWpUmBRLrIDjedzx7/CShq0bRDS2gI4FIs77VHLVQ==
+  dependencies:
+    "@babel/helper-plugin-utils" "^7.0.0"
+    "@babel/plugin-syntax-nullish-coalescing-operator" "^7.7.4"
+
 "@babel/plugin-proposal-object-rest-spread@^7.0.0":
   version "7.5.5"
   resolved "https://registry.yarnpkg.com/@babel/plugin-proposal-object-rest-spread/-/plugin-proposal-object-rest-spread-7.5.5.tgz#61939744f71ba76a3ae46b5eea18a54c16d22e58"
@@ -497,6 +505,13 @@
   dependencies:
     "@babel/helper-plugin-utils" "^7.0.0"
 
+"@babel/plugin-syntax-nullish-coalescing-operator@^7.7.4":
+  version "7.7.4"
+  resolved "https://registry.yarnpkg.com/@babel/plugin-syntax-nullish-coalescing-operator/-/plugin-syntax-nullish-coalescing-operator-7.7.4.tgz#e53b751d0c3061b1ba3089242524b65a7a9da12b"
+  integrity sha512-XKh/yIRPiQTOeBg0QJjEus5qiSKucKAiApNtO1psqG7D17xmE+X2i5ZqBEuSvo0HRuyPaKaSN/Gy+Ha9KFQolw==
+  dependencies:
+    "@babel/helper-plugin-utils" "^7.0.0"
+
 "@babel/plugin-syntax-object-rest-spread@^7.0.0", "@babel/plugin-syntax-object-rest-spread@^7.2.0":
   version "7.2.0"
   resolved "https://registry.yarnpkg.com/@babel/plugin-syntax-object-rest-spread/-/plugin-syntax-object-rest-spread-7.2.0.tgz#3b7a3e733510c57e820b9142a6579ac8b0dfad2e"