Add a check for parentheses for AwaitExpressions (fixes T6913)

packages/babel-generator/src/node/parentheses.js

@@ -144,6 +144,16 @@ export function SequenceExpression(node: Object, parent: Object): boolean {
   return true;
 }
 
+export function AwaitExpression(node: Object, parent: Object): boolean {
+  return t.isBinary(parent) ||
+         t.isUnaryLike(parent) ||
+         t.isCallExpression(parent) ||
+         t.isMemberExpression(parent) ||
+         t.isNewExpression(parent) ||
+         t.isConditionalExpression(parent) ||
+         t.isAwaitExpression(parent);
+}
+
 export function YieldExpression(node: Object, parent: Object): boolean {
   return t.isBinary(parent) ||
          t.isUnaryLike(parent) ||

packages/babel-generator/test/fixtures/parentheses/await-expression/actual.js

@@ -0,0 +1,11 @@
+async function asdf() {
+  (await 1) || (await 2);
+  (await b)();
+  new (await b)();
+  true ? (await 1) : (await 2);
+  await (await 1);
+}
+
+async function a(b) {
+  (await xhr({ url: "views/test.html" })).data;
+}

packages/babel-generator/test/fixtures/parentheses/await-expression/expected.js

@@ -0,0 +1,11 @@
+async function asdf() {
+  (await 1) || (await 2);
+  (await b)();
+  new (await b)();
+  true ? (await 1) : (await 2);
+  await (await 1);
+}
+
+async function a(b) {
+  (await xhr({ url: "views/test.html" })).data;
+}