From 7cddfe84ca6a77d4d536a6c4f4eae6004ff085b4 Mon Sep 17 00:00:00 2001
From: Ilya Rodionov <ris58h@gmail.com>
Date: Mon, 12 Jun 2023 13:14:11 +0300
Subject: [PATCH] [javascript] Class elements (fixes #3474, fixes #3451)

---
 javascript/javascript/JavaScriptParser.g4     | 34 +++++++++++++++----
 javascript/javascript/examples/AsyncAwait.js  |  3 +-
 javascript/javascript/examples/ClassFields.js | 13 +++++++
 javascript/javascript/examples/ClassStatic.js | 12 +++++++
 4 files changed, 53 insertions(+), 9 deletions(-)
 create mode 100644 javascript/javascript/examples/ClassFields.js
 create mode 100644 javascript/javascript/examples/ClassStatic.js

diff --git a/javascript/javascript/JavaScriptParser.g4 b/javascript/javascript/JavaScriptParser.g4
index 031438724d..001687c056 100644
--- a/javascript/javascript/JavaScriptParser.g4
+++ b/javascript/javascript/JavaScriptParser.g4
@@ -262,15 +262,29 @@ classTail
     ;
 
 classElement
-    : (Static | {this.n("static")}? identifier | Async)* (methodDefinition | assignable '=' objectLiteral ';')
+    : (Static | {this.n("static")}? identifier)? methodDefinition
+    | (Static | {this.n("static")}? identifier)? fieldDefinition
+    | (Static | {this.n("static")}? identifier) block
     | emptyStatement_
-    | '#'? propertyName '=' singleExpression
     ;
 
 methodDefinition
-    : '*'? '#'? propertyName '(' formalParameterList? ')' functionBody
-    | '*'? '#'? getter '(' ')' functionBody
-    | '*'? '#'? setter '(' formalParameterList? ')' functionBody
+    : (Async {this.notLineTerminator()}?)? '*'? classElementName '(' formalParameterList? ')' functionBody
+    | '*'? getter '(' ')' functionBody
+    | '*'? setter '(' formalParameterList? ')' functionBody
+    ;
+
+fieldDefinition
+    : classElementName initializer?
+    ;
+
+classElementName
+    : propertyName
+    | privateIdentifier
+    ;
+
+privateIdentifier
+    : '#' identifierName
     ;
 
 formalParameterList
@@ -386,6 +400,12 @@ singleExpression
     | '(' expressionSequence ')'                                            # ParenthesizedExpression
     ;
 
+initializer
+// TODO: must be `= AssignmentExpression` and we have such label alredy but it doesn't respect the specification.
+//  See https://tc39.es/ecma262/multipage/ecmascript-language-expressions.html#prod-Initializer
+    : '=' singleExpression
+    ;
+
 assignable
     : identifier
     | arrayLiteral
@@ -461,11 +481,11 @@ bigintLiteral
     ;
 
 getter
-    : {this.n("get")}? identifier propertyName
+    : {this.n("get")}? identifier classElementName
     ;
 
 setter
-    : {this.n("set")}? identifier propertyName
+    : {this.n("set")}? identifier classElementName
     ;
 
 identifierName
diff --git a/javascript/javascript/examples/AsyncAwait.js b/javascript/javascript/examples/AsyncAwait.js
index ad96ee20a5..b734e3442a 100644
--- a/javascript/javascript/examples/AsyncAwait.js
+++ b/javascript/javascript/examples/AsyncAwait.js
@@ -3,9 +3,8 @@ async function f(){}
 class C {
     async method(){}
     static async method1(){}
-    async static #method2(){}
+    static async #method2(){}
     async *gen(){}
-    async get v(){return 1};
 }
 async ()=>{};
 
diff --git a/javascript/javascript/examples/ClassFields.js b/javascript/javascript/examples/ClassFields.js
new file mode 100644
index 0000000000..500692bd7c
--- /dev/null
+++ b/javascript/javascript/examples/ClassFields.js
@@ -0,0 +1,13 @@
+const PREFIX = "prefix";
+
+class ClassWithField {
+  field;
+  fieldWithInitializer = "instance field";
+  [`${PREFIX}Field`] = "prefixed field";
+}
+
+const instance = new ClassWithField();
+console.log(Object.hasOwn(instance, "field")); // true
+console.log(instance.field); // undefined
+console.log(instance.fieldWithInitializer); // "instance field"
+console.log(instance.prefixField); // "prefixed field"
diff --git a/javascript/javascript/examples/ClassStatic.js b/javascript/javascript/examples/ClassStatic.js
new file mode 100644
index 0000000000..15d3104627
--- /dev/null
+++ b/javascript/javascript/examples/ClassStatic.js
@@ -0,0 +1,12 @@
+class ClassWithStaticInitializationBlock {
+  static staticProperty1 = 'Property 1';
+  static staticProperty2;
+  static {
+    this.staticProperty2 = 'Property 2';
+  }
+}
+
+console.log(ClassWithStaticInitializationBlock.staticProperty1);
+// Expected output: "Property 1"
+console.log(ClassWithStaticInitializationBlock.staticProperty2);
+// Expected output: "Property 2"
\ No newline at end of file