Fix code generation for async generator methods (#6998)

Fixes generator to write `async *foo() {}` instead of `*async foo() {}`.

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

@@ -31,12 +31,6 @@ export function _methodHead(node: Object) {
   const kind = node.kind;
   const key = node.key;
 
-  if (kind === "method" || kind === "init") {
-    if (node.generator) {
-      this.token("*");
-    }
-  }
-
   if (kind === "get" || kind === "set") {
     this.word(kind);
     this.space();
@@ -47,6 +41,12 @@ export function _methodHead(node: Object) {
     this.space();
   }
 
+  if (kind === "method" || kind === "init") {
+    if (node.generator) {
+      this.token("*");
+    }
+  }
+
   if (node.computed) {
     this.token("[");
     this.print(key, node);

packages/babel-generator/test/fixtures/edgecase/async-generator/actual.js

@@ -0,0 +1,19 @@
+function a() {}
+function *b() {}
+async function c() {}
+async function *d() {}
+var e = function () {};
+var f = function *() {};
+var g = async function () {};
+var h = async function *() {};
+
+class A {
+  a() {}
+  *b() {}
+  async c() {}
+  async *d() {}
+  e = () => {};
+  // f = () =>* {};
+  g = async () => {};
+  // h = async () =>* {};
+}

packages/babel-generator/test/fixtures/edgecase/async-generator/expected.js

@@ -0,0 +1,30 @@
+function a() {}
+
+function* b() {}
+
+async function c() {}
+
+async function* d() {}
+
+var e = function () {};
+
+var f = function* () {};
+
+var g = async function () {};
+
+var h = async function* () {};
+
+class A {
+  a() {}
+
+  *b() {}
+
+  async c() {}
+
+  async *d() {}
+
+  e = () => {}; // f = () =>* {};
+
+  g = async () => {}; // h = async () =>* {};
+
+}

packages/babel-generator/test/fixtures/edgecase/async-generator/options.json

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