Improve formatting for AssignmentExpression with ClassExpression that has long superClass (#9341)

* Improve formatting for AssignmentExpression with ClassExpression that has long superClass

Fix by prettier

* Add changelog

* Remove unnecesary concat call

* Mention abount Google Closure Library in changelog

changelog_unreleased/javascript/pr-9341.md

@@ -0,0 +1,33 @@
+#### Improve formatting for `AssignmentExpression` with `ClassExpression` that has a long super class (#9341 by @sosukesuzuki)
+
+This improves the formatting for [Google Closure Library Namespace](https://developers.google.com/closure/library/docs/introduction#names).
+
+<!-- prettier-ignore -->
+```js
+// Input
+aaaaaaaa.bbbbbbbb.cccccccc.dddddddd.eeeeeeee.ffffffff.gggggggg2 = class extends (
+  aaaaaaaa.bbbbbbbb.cccccccc.dddddddd.eeeeeeee.ffffffff.gggggggg1
+) {
+  method () {
+    console.log("foo");
+  }
+};
+
+// Prettier stable
+aaaaaaaa.bbbbbbbb.cccccccc.dddddddd.eeeeeeee.ffffffff.gggggggg2 = class extends aaaaaaaa
+  .bbbbbbbb.cccccccc.dddddddd.eeeeeeee.ffffffff.gggggggg1 {
+  method() {
+    console.log("foo");
+  }
+};
+
+// Prettier master
+aaaaaaaa.bbbbbbbb.cccccccc.dddddddd.eeeeeeee.ffffffff.gggggggg2 = class extends (
+  aaaaaaaa.bbbbbbbb.cccccccc.dddddddd.eeeeeeee.ffffffff.gggggggg1
+) {
+  method() {
+    console.log("foo");
+  }
+};
+
+```

src/language-js/printer-estree.js

@@ -4322,9 +4322,22 @@ function printClass(path, options, print) {
   }
 
   if (n.superClass) {
+    const printSuperClass = (path) => {
+      const printed = path.call(print, "superClass");
+      const parent = path.getParentNode();
+      if (parent && parent.type === "AssignmentExpression") {
+        return concat([
+          ifBreak("("),
+          indent(concat([softline, printed])),
+          softline,
+          ifBreak(")"),
+        ]);
+      }
+      return printed;
+    };
     const printed = concat([
       "extends ",
-      path.call(print, "superClass"),
+      printSuperClass(path),
       path.call(print, "superTypeParameters"),
     ]);
     const printedWithComments = path.call(

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

@@ -1,5 +1,73 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`assignment.js format 1`] = `
+====================================options=====================================
+parsers: ["babel", "flow", "typescript"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+aaaaaaaa.bbbbbbbb.cccccccc.dddddddd.eeeeeeee.ffffffff.gggggggg2 = class extends (
+  aaaaaaaa.bbbbbbbb.cccccccc.dddddddd.eeeeeeee.ffffffff.gggggggg1
+) {
+  method () {
+    console.log("foo");
+  }
+};
+
+foo = class extends bar {
+  method() {
+    console.log("foo");
+  }
+};
+
+aaaaaaaa.bbbbbbbb.cccccccc.dddddddd.eeeeeeee.ffffffff.gggggggg2 = class extends bar {
+  method() {
+    console.log("foo");
+  }
+};
+
+foo = class extends aaaaaaaa.bbbbbbbb.cccccccc.dddddddd.eeeeeeee.ffffffff.gggggggg2 {
+  method() {
+    console.log("foo");
+  }
+};
+
+=====================================output=====================================
+aaaaaaaa.bbbbbbbb.cccccccc.dddddddd.eeeeeeee.ffffffff.gggggggg2 = class extends (
+  aaaaaaaa.bbbbbbbb.cccccccc.dddddddd.eeeeeeee.ffffffff.gggggggg1
+) {
+  method() {
+    console.log("foo");
+  }
+};
+
+foo = class extends (
+  bar
+) {
+  method() {
+    console.log("foo");
+  }
+};
+
+aaaaaaaa.bbbbbbbb.cccccccc.dddddddd.eeeeeeee.ffffffff.gggggggg2 = class extends (
+  bar
+) {
+  method() {
+    console.log("foo");
+  }
+};
+
+foo = class extends (
+  aaaaaaaa.bbbbbbbb.cccccccc.dddddddd.eeeeeeee.ffffffff.gggggggg2
+) {
+  method() {
+    console.log("foo");
+  }
+};
+
+================================================================================
+`;
+
 exports[`binary.js format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]

tests/js/classes/assignment.js

@@ -0,0 +1,25 @@
+aaaaaaaa.bbbbbbbb.cccccccc.dddddddd.eeeeeeee.ffffffff.gggggggg2 = class extends (
+  aaaaaaaa.bbbbbbbb.cccccccc.dddddddd.eeeeeeee.ffffffff.gggggggg1
+) {
+  method () {
+    console.log("foo");
+  }
+};
+
+foo = class extends bar {
+  method() {
+    console.log("foo");
+  }
+};
+
+aaaaaaaa.bbbbbbbb.cccccccc.dddddddd.eeeeeeee.ffffffff.gggggggg2 = class extends bar {
+  method() {
+    console.log("foo");
+  }
+};
+
+foo = class extends aaaaaaaa.bbbbbbbb.cccccccc.dddddddd.eeeeeeee.ffffffff.gggggggg2 {
+  method() {
+    console.log("foo");
+  }
+};