Handle throw expressions in generator (#8727)

Fixes #8716

packages/babel-generator/src/generators/expressions.js

@@ -5,7 +5,9 @@ export function UnaryExpression(node: Object) {
   if (
     node.operator === "void" ||
     node.operator === "delete" ||
-    node.operator === "typeof"
+    node.operator === "typeof" ||
+    // throwExpressions
+    node.operator === "throw"
   ) {
     this.word(node.operator);
     this.space();

packages/babel-generator/test/fixtures/regression/throw-expression/input.js

@@ -0,0 +1 @@
+() => throw new X();

packages/babel-generator/test/fixtures/regression/throw-expression/options.json

@@ -0,0 +1 @@
+{ "plugins": ["throwExpressions"] }

packages/babel-generator/test/fixtures/regression/throw-expression/output.js

@@ -0,0 +1 @@
+() => throw new X();