Add parenthesis for yield and await inside of `as` (#1915)

Fixes #1913

src/fast-path.js

@@ -354,7 +354,8 @@ FastPath.prototype.needsParens = function() {
     case "YieldExpression":
       if (
         parent.type === "UnaryExpression" ||
-        parent.type === "AwaitExpression"
+        parent.type === "AwaitExpression" ||
+        parent.type === "TSAsExpression"
       ) {
         return true;
       }
@@ -366,6 +367,7 @@ FastPath.prototype.needsParens = function() {
         case "LogicalExpression":
         case "SpreadElement":
         case "SpreadProperty":
+        case "TSAsExpression":
           return true;
 
         case "MemberExpression":

tests/typescript_as/__snapshots__/jsfmt.spec.js.snap

@@ -9,6 +9,12 @@ start + (yearSelectTotal as number)
 scrollTop > (visibilityHeight as number)
 export default class Column<T> extends (RcTable.Column as React.ComponentClass<ColumnProps<T>>) {}
 ({}) as {};
+function*g() {
+  const test = (yield 'foo') as number;
+}
+async function g() {
+  const test = (await 'foo') as number;
+}
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 const name = (description as DescriptionObject).name || (description as string);
 this.isTabActionBar((e.target || e.srcElement) as HTMLElement);
@@ -22,5 +28,11 @@ export default class Column<T> extends (RcTable.Column as React.ComponentClass<
   ColumnProps<T>
 >) {}
 ({}) as {};
+function* g() {
+  const test = (yield "foo") as number;
+}
+async function g() {
+  const test = (await "foo") as number;
+}
 
 `;

tests/typescript_as/as.js

@@ -6,3 +6,9 @@ start + (yearSelectTotal as number)
 scrollTop > (visibilityHeight as number)
 export default class Column<T> extends (RcTable.Column as React.ComponentClass<ColumnProps<T>>) {}
 ({}) as {};
+function*g() {
+  const test = (yield 'foo') as number;
+}
+async function g() {
+  const test = (await 'foo') as number;
+}