Avoid IIFE for single-expression class static blocks

packages/babel-helper-create-class-features-plugin/src/fields.ts

@@ -993,12 +993,17 @@ export function buildFieldsInitNodes(
     // a `NodePath<t.StaticBlock>`
     // this maybe a bug for ts
     switch (true) {
-      case isStaticBlock:
-        staticNodes.push(
-          // @ts-expect-error prop is `StaticBlock` here
-          template.statement.ast`(() => ${t.blockStatement(prop.node.body)})()`,
-        );
+      case isStaticBlock: {
+        const blockBody = (prop.node as t.StaticBlock).body;
+        // We special-case the single expression case to avoid the iife, since
+        // it's common.
+        if (blockBody.length === 1 && t.isExpressionStatement(blockBody[0])) {
+          staticNodes.push(blockBody[0] as t.ExpressionStatement);
+        } else {
+          staticNodes.push(template.statement.ast`(() => { ${blockBody} })()`);
+        }
         break;
+      }
       case isStatic && isPrivate && isField && privateFieldsAsProperties:
         needsClassRef = true;
         staticNodes.push(

packages/babel-plugin-proposal-class-static-block/src/index.ts

@@ -59,12 +59,21 @@ export default declare(({ types: t, template, assertVersion }) => {
           const staticBlockRef = t.privateName(
             t.identifier(staticBlockPrivateId),
           );
+
+          let replacement;
+          const blockBody = path.node.body;
+          // We special-case the single expression case to avoid the iife, since
+          // it's common.
+          if (blockBody.length === 1 && t.isExpressionStatement(blockBody[0])) {
+            replacement = (blockBody[0] as t.ExpressionStatement).expression;
+          } else {
+            replacement = template.expression.ast`(() => { ${blockBody} })()`;
+          }
+
           path.replaceWith(
             t.classPrivateProperty(
               staticBlockRef,
-              template.expression.ast`(() => { ${
-                (path.node as t.StaticBlock).body
-              } })()`,
+              replacement,
               [],
               /* static */ true,
             ),

packages/babel-plugin-proposal-class-static-block/test/fixtures/class-static-block/class-binding/output.js

@@ -1,8 +1,6 @@
 class Foo {
   static bar = 42;
-  static #_ = (() => {
-    this.foo = Foo.bar;
-  })();
+  static #_ = this.foo = Foo.bar;
 }
 
 expect(Foo.foo).toBe(42);

packages/babel-plugin-proposal-class-static-block/test/fixtures/class-static-block/class-declaration/output.js

@@ -1,8 +1,6 @@
 class Foo {
   static bar = 42;
-  static #_ = (() => {
-    this.foo = this.bar;
-  })();
+  static #_ = this.foo = this.bar;
 }
 
 expect(Foo.foo).toBe(42);

packages/babel-plugin-proposal-class-static-block/test/fixtures/class-static-block/in-class-heritage/output.js

@@ -1,15 +1,9 @@
 class Foo extends class extends class Base {
-  static #_ = (() => {
-    this.qux = 21;
-  })();
+  static #_ = this.qux = 21;
 } {
-  static #_ = (() => {
-    this.bar = 21;
-  })();
+  static #_ = this.bar = 21;
 } {
-  static #_ = (() => {
-    this.foo = this.bar + this.qux;
-  })();
+  static #_ = this.foo = this.bar + this.qux;
 }
 
 expect(Foo.foo).toBe(42);

packages/babel-plugin-proposal-class-static-block/test/fixtures/class-static-block/multiple-static-initializers/output.js

@@ -5,7 +5,5 @@ class Foo {
     this.qux1 = this.qux;
   })();
   static qux = 21;
-  static #_2 = (() => {
-    this.qux2 = this.qux;
-  })();
+  static #_2 = this.qux2 = this.qux;
 }

packages/babel-plugin-proposal-class-static-block/test/fixtures/class-static-block/name-conflict/output.js

@@ -1,9 +1,7 @@
 class Foo {
   static #_ = 42; // static block can not be tranformed as `#_` here
 
-  static #_2 = (() => {
-    this.foo = this.#_;
-  })();
+  static #_2 = this.foo = this.#_;
 }
 
 expect(Foo.foo).toBe(42);

packages/babel-plugin-proposal-class-static-block/test/fixtures/class-static-block/new-target/output.js

@@ -1,9 +1,7 @@
 class Base {
   constructor() {
     this.Foo = class {
-      static #_ = (() => {
-        this.foo = new.target;
-      })();
+      static #_ = this.foo = new.target;
     };
   }
 

packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/class-binding/output.js

@@ -1,9 +1,5 @@
 class Foo {}
 
 Foo.bar = 42;
-
-(() => {
-  Foo.foo = Foo.bar;
-})();
-
+Foo.foo = Foo.bar;
 expect(Foo.foo).toBe(42);

packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/class-declaration/output.js

@@ -1,9 +1,5 @@
 class Foo {}
 
 Foo.bar = 42;
-
-(() => {
-  Foo.foo = Foo.bar;
-})();
-
+Foo.foo = Foo.bar;
 expect(Foo.foo).toBe(42);

packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/in-class-heritage/output.js

@@ -1,13 +1,6 @@
 var _class, _class2;
 
-class Foo extends (_class = class extends (_class2 = class Base {}, (() => {
-  _class2.qux = 21;
-})(), _class2) {}, (() => {
-  _class.bar = 21;
-})(), _class) {}
-
-(() => {
-  Foo.foo = Foo.bar + Foo.qux;
-})();
+class Foo extends (_class = class extends (_class2 = class Base {}, _class2.qux = 21, _class2) {}, _class.bar = 21, _class) {}
 
+Foo.foo = Foo.bar + Foo.qux;
 expect(Foo.foo).toBe(42);

packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/multiple-static-initializers/output.js

@@ -13,7 +13,4 @@ Object.defineProperty(Foo, _bar, {
 })();
 
 Foo.qux = 21;
-
-(() => {
-  Foo.qux2 = Foo.qux;
-})();
+Foo.qux2 = Foo.qux;

packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/name-conflict/output.js

@@ -6,9 +6,5 @@ Object.defineProperty(Foo, _, {
   writable: true,
   value: 42
 });
-
-(() => {
-  Foo.foo = babelHelpers.classPrivateFieldLooseBase(Foo, _)[_];
-})();
-
+Foo.foo = babelHelpers.classPrivateFieldLooseBase(Foo, _)[_];
 expect(Foo.foo).toBe(42);

packages/babel-plugin-proposal-class-static-block/test/fixtures/integration-loose/super-static-block/output.js

@@ -1,13 +1,7 @@
 var _ref, _class;
 
-class Foo extends (_ref = (_class = class _ref {}, (() => {
-  _class.bar = 42;
-})(), _class)) {}
+class Foo extends (_ref = (_class = class _ref {}, _class.bar = 42, _class)) {}
 
 Foo.bar = 21;
-
-(() => {
-  Foo.foo = _ref.bar;
-})();
-
+Foo.foo = _ref.bar;
 expect(Foo.foo).toBe(42);

packages/babel-plugin-proposal-class-static-block/test/fixtures/integration/class-binding/output.js

@@ -1,9 +1,5 @@
 class Foo {}
 
 babelHelpers.defineProperty(Foo, "bar", 42);
-
-(() => {
-  Foo.foo = Foo.bar;
-})();
-
+Foo.foo = Foo.bar;
 expect(Foo.foo).toBe(42);

packages/babel-plugin-proposal-class-static-block/test/fixtures/integration/class-declaration/output.js

@@ -1,9 +1,5 @@
 class Foo {}
 
 babelHelpers.defineProperty(Foo, "bar", 42);
-
-(() => {
-  Foo.foo = Foo.bar;
-})();
-
+Foo.foo = Foo.bar;
 expect(Foo.foo).toBe(42);

packages/babel-plugin-proposal-class-static-block/test/fixtures/integration/in-class-heritage/output.js

@@ -1,13 +1,6 @@
 var _class, _class2;
 
-class Foo extends (_class = class extends (_class2 = class Base {}, (() => {
-  _class2.qux = 21;
-})(), _class2) {}, (() => {
-  _class.bar = 21;
-})(), _class) {}
-
-(() => {
-  Foo.foo = Foo.bar + Foo.qux;
-})();
+class Foo extends (_class = class extends (_class2 = class Base {}, _class2.qux = 21, _class2) {}, _class.bar = 21, _class) {}
 
+Foo.foo = Foo.bar + Foo.qux;
 expect(Foo.foo).toBe(42);

packages/babel-plugin-proposal-class-static-block/test/fixtures/integration/multiple-static-initializers/output.js

@@ -11,7 +11,4 @@ var _bar = {
 })();
 
 babelHelpers.defineProperty(Foo, "qux", 21);
-
-(() => {
-  Foo.qux2 = Foo.qux;
-})();
+Foo.qux2 = Foo.qux;

packages/babel-plugin-proposal-class-static-block/test/fixtures/integration/name-conflict/output.js

@@ -4,9 +4,5 @@ var _ = {
   writable: true,
   value: 42
 };
-
-(() => {
-  Foo.foo = babelHelpers.classStaticPrivateFieldSpecGet(Foo, Foo, _);
-})();
-
+Foo.foo = babelHelpers.classStaticPrivateFieldSpecGet(Foo, Foo, _);
 expect(Foo.foo).toBe(42);

packages/babel-plugin-proposal-class-static-block/test/fixtures/integration/new-target/output.js

@@ -2,9 +2,7 @@ class Base {
   constructor() {
     var _class;
 
-    this.Foo = (_class = class {}, (() => {
-      _class.foo = void 0;
-    })(), _class);
+    this.Foo = (_class = class {}, _class.foo = void 0, _class);
   }
 
 }

packages/babel-plugin-proposal-class-static-block/test/plugin-ordering.test.js

@@ -26,9 +26,7 @@ describe("plugin ordering", () => {
 
       class Foo {}
 
-      (() => {
-        Foo.foo = Foo.bar;
-      })();
+      Foo.foo = Foo.bar;
 
       _defineProperty(Foo, \\"bar\\", 42);"
     `);

packages/babel-plugin-proposal-decorators/test/fixtures/2021-12-accessors--to-es2015/private/output.js

@@ -48,14 +48,12 @@ function _get_b2() {
   _get_b(this);
 }
 
-(() => {
-  [_init_a, _get_a, _set_a, _init_b, _get_b, _set_b, _initProto] = babelHelpers.applyDecs(Foo, [[dec, 1, "a", function () {
-    return babelHelpers.classPrivateFieldGet(this, _A);
-  }, function (value) {
-    babelHelpers.classPrivateFieldSet(this, _A, value);
-  }], [dec, 1, "b", function () {
-    return babelHelpers.classPrivateFieldGet(this, _B);
-  }, function (value) {
-    babelHelpers.classPrivateFieldSet(this, _B, value);
-  }]], []);
-})();
+[_init_a, _get_a, _set_a, _init_b, _get_b, _set_b, _initProto] = babelHelpers.applyDecs(Foo, [[dec, 1, "a", function () {
+  return babelHelpers.classPrivateFieldGet(this, _A);
+}, function (value) {
+  babelHelpers.classPrivateFieldSet(this, _A, value);
+}], [dec, 1, "b", function () {
+  return babelHelpers.classPrivateFieldGet(this, _B);
+}, function (value) {
+  babelHelpers.classPrivateFieldSet(this, _B, value);
+}]], []);

packages/babel-plugin-proposal-decorators/test/fixtures/2021-12-accessors--to-es2015/public/output.js

@@ -52,6 +52,4 @@ class Foo {
 
 }
 
-(() => {
-  [_init_a, _init_b, _init_computedKey, _initProto] = babelHelpers.applyDecs(Foo, [[dec, 1, "a"], [dec, 1, "b"], [dec, 1, _computedKey]], []);
-})();
+[_init_a, _init_b, _init_computedKey, _initProto] = babelHelpers.applyDecs(Foo, [[dec, 1, "a"], [dec, 1, "b"], [dec, 1, _computedKey]], []);

packages/babel-plugin-proposal-decorators/test/fixtures/2021-12-classes--to-es2015/expressions/output.js

@@ -2,52 +2,16 @@ var _initClass, _A, _class, _initClass2, _C, _class2, _initClass3, _D, _class3,
 
 const dec = () => {};
 
-const A = ((_class = class A {}, (() => {
-  [_A, _initClass] = babelHelpers.applyDecs(_class, [], [dec]);
-})(), (() => {
-  _initClass();
-})()), _A);
-const B = ((_class2 = class C {}, (() => {
-  [_C, _initClass2] = babelHelpers.applyDecs(_class2, [], [dec]);
-})(), (() => {
-  _initClass2();
-})()), _C);
-const D = ((_class3 = class D {}, (() => {
-  [_D, _initClass3] = babelHelpers.applyDecs(_class3, [], [dec]);
-})(), (() => {
-  _initClass3();
-})()), _D);
-const E = (((_class4 = class {}, (() => {
-  [_decorated_class, _initClass4] = babelHelpers.applyDecs(_class4, [], [dec]);
-})(), (() => {
-  _initClass4();
-})()), _decorated_class), 123);
-const F = [((_class5 = class G {}, (() => {
-  [_G, _initClass5] = babelHelpers.applyDecs(_class5, [], [dec]);
-})(), (() => {
-  _initClass5();
-})()), _G), ((_class6 = class {}, (() => {
-  [_decorated_class2, _initClass6] = babelHelpers.applyDecs(_class6, [], [dec]);
-})(), (() => {
-  _initClass6();
-})()), _decorated_class2)];
-const H = ((_class7 = class H extends I {}, (() => {
-  [_H, _initClass7] = babelHelpers.applyDecs(_class7, [], [dec]);
-})(), (() => {
-  _initClass7();
-})()), _H);
-const J = ((_class8 = class K extends L {}, (() => {
-  [_K, _initClass8] = babelHelpers.applyDecs(_class8, [], [dec]);
-})(), (() => {
-  _initClass8();
-})()), _K);
+const A = ((_class = class A {}, [_A, _initClass] = babelHelpers.applyDecs(_class, [], [dec]), _initClass()), _A);
+const B = ((_class2 = class C {}, [_C, _initClass2] = babelHelpers.applyDecs(_class2, [], [dec]), _initClass2()), _C);
+const D = ((_class3 = class D {}, [_D, _initClass3] = babelHelpers.applyDecs(_class3, [], [dec]), _initClass3()), _D);
+const E = (((_class4 = class {}, [_decorated_class, _initClass4] = babelHelpers.applyDecs(_class4, [], [dec]), _initClass4()), _decorated_class), 123);
+const F = [((_class5 = class G {}, [_G, _initClass5] = babelHelpers.applyDecs(_class5, [], [dec]), _initClass5()), _G), ((_class6 = class {}, [_decorated_class2, _initClass6] = babelHelpers.applyDecs(_class6, [], [dec]), _initClass6()), _decorated_class2)];
+const H = ((_class7 = class H extends I {}, [_H, _initClass7] = babelHelpers.applyDecs(_class7, [], [dec]), _initClass7()), _H);
+const J = ((_class8 = class K extends L {}, [_K, _initClass8] = babelHelpers.applyDecs(_class8, [], [dec]), _initClass8()), _K);
 
 function classFactory() {
   var _initClass9, _decorated_class3, _class9;
 
-  return (_class9 = class {}, (() => {
-    [_decorated_class3, _initClass9] = babelHelpers.applyDecs(_class9, [], [dec]);
-  })(), (() => {
-    _initClass9();
-  })()), _decorated_class3;
+  return (_class9 = class {}, [_decorated_class3, _initClass9] = babelHelpers.applyDecs(_class9, [], [dec]), _initClass9()), _decorated_class3;
 }

packages/babel-plugin-proposal-decorators/test/fixtures/2021-12-classes--to-es2015/inheritance/output.js

@@ -8,22 +8,14 @@ let _Bar;
 
 class Bar {}
 
-(() => {
-  [_Bar, _initClass] = babelHelpers.applyDecs(Bar, [], [dec1]);
-})();
+[_Bar, _initClass] = babelHelpers.applyDecs(Bar, [], [dec1]);
 
-(() => {
-  _initClass();
-})();
+_initClass();
 
 let _Foo;
 
 class Foo extends _Bar {}
 
-(() => {
-  [_Foo, _initClass2] = babelHelpers.applyDecs(Foo, [], [dec2]);
-})();
+[_Foo, _initClass2] = babelHelpers.applyDecs(Foo, [], [dec2]);
 
-(() => {
-  _initClass2();
-})();
+_initClass2();