Add support for ClassPrivateProperty (#2837)

src/fast-path.js

@@ -622,6 +622,7 @@ function isStatement(node) {
     node.type === "ClassDeclaration" ||
     node.type === "ClassMethod" ||
     node.type === "ClassProperty" ||
+    node.type === "ClassPrivateProperty" ||
     node.type === "ContinueStatement" ||
     node.type === "DebuggerStatement" ||
     node.type === "DeclareClass" ||

src/parser-babylon.js

@@ -25,7 +25,8 @@ function parse(text, parsers, opts) {
       "numericSeparator",
       "importMeta",
       "optionalCatchBinding",
-      "optionalChaining"
+      "optionalChaining",
+      "classPrivateProperties"
     ]
   };
 

src/printer.js

@@ -1809,7 +1809,8 @@ function genericPrintNoParens(path, options, print, args) {
         "}"
       ]);
     case "ClassProperty":
-    case "TSAbstractClassProperty": {
+    case "TSAbstractClassProperty":
+    case "ClassPrivateProperty": {
       if (n.accessibility) {
         parts.push(n.accessibility + " ");
       }
@@ -2725,6 +2726,9 @@ function genericPrintNoParens(path, options, print, args) {
         return printStatementSequence(bodyPath, options, print);
       }, "body");
 
+    case "PrivateName":
+      return concat(["#", path.call(print, "id")]);
+
     default:
       /* istanbul ignore next */
       throw new Error("unknown type: " + JSON.stringify(n.type));

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

@@ -0,0 +1,175 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`private_fields.js 1`] = `
+class A { #x; #y; }
+class B { #x = 0; #y = 1; }
+
+class C {
+  static #x;
+  static #y = 1;
+}
+
+class D {
+  #x
+  #y
+}
+
+class Point {
+  #x = 1;
+  #y = 2;
+
+  constructor(x = 0, y = 0) {
+    this.#x = +x;
+    this.#y = +y;
+  }
+
+  get x() { return this.#x }
+  set x(value) { this.#x = +value }
+
+  get y() { return this.#y }
+  set y(value) { this.#y = +value }
+
+  equals(p) { return this.#x === p.#x && this.#y === p.#y }
+
+  toString() { return \`Point<\${ this.#x },\${ this.#y }>\` }
+}
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+class A {
+  #x;
+  #y;
+}
+class B {
+  #x = 0;
+  #y = 1;
+}
+
+class C {
+  static #x;
+  static #y = 1;
+}
+
+class D {
+  #x;
+  #y;
+}
+
+class Point {
+  #x = 1;
+  #y = 2;
+
+  constructor(x = 0, y = 0) {
+    this.#x = +x;
+    this.#y = +y;
+  }
+
+  get x() {
+    return this.#x;
+  }
+  set x(value) {
+    this.#x = +value;
+  }
+
+  get y() {
+    return this.#y;
+  }
+  set y(value) {
+    this.#y = +value;
+  }
+
+  equals(p) {
+    return this.#x === p.#x && this.#y === p.#y;
+  }
+
+  toString() {
+    return \`Point<\${this.#x},\${this.#y}>\`;
+  }
+}
+
+`;
+
+exports[`private_fields.js 2`] = `
+class A { #x; #y; }
+class B { #x = 0; #y = 1; }
+
+class C {
+  static #x;
+  static #y = 1;
+}
+
+class D {
+  #x
+  #y
+}
+
+class Point {
+  #x = 1;
+  #y = 2;
+
+  constructor(x = 0, y = 0) {
+    this.#x = +x;
+    this.#y = +y;
+  }
+
+  get x() { return this.#x }
+  set x(value) { this.#x = +value }
+
+  get y() { return this.#y }
+  set y(value) { this.#y = +value }
+
+  equals(p) { return this.#x === p.#x && this.#y === p.#y }
+
+  toString() { return \`Point<\${ this.#x },\${ this.#y }>\` }
+}
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+class A {
+  #x
+  #y
+}
+class B {
+  #x = 0
+  #y = 1
+}
+
+class C {
+  static #x
+  static #y = 1
+}
+
+class D {
+  #x
+  #y
+}
+
+class Point {
+  #x = 1
+  #y = 2
+
+  constructor(x = 0, y = 0) {
+    this.#x = +x
+    this.#y = +y
+  }
+
+  get x() {
+    return this.#x
+  }
+  set x(value) {
+    this.#x = +value
+  }
+
+  get y() {
+    return this.#y
+  }
+  set y(value) {
+    this.#y = +value
+  }
+
+  equals(p) {
+    return this.#x === p.#x && this.#y === p.#y
+  }
+
+  toString() {
+    return \`Point<\${this.#x},\${this.#y}>\`
+  }
+}
+
+`;

tests/classes_private_fields/jsfmt.spec.js

@@ -0,0 +1,2 @@
+run_spec(__dirname, { parser: "babylon" });
+run_spec(__dirname, { semi: false, parser: "babylon" });

tests/classes_private_fields/private_fields.js

@@ -0,0 +1,32 @@
+class A { #x; #y; }
+class B { #x = 0; #y = 1; }
+
+class C {
+  static #x;
+  static #y = 1;
+}
+
+class D {
+  #x
+  #y
+}
+
+class Point {
+  #x = 1;
+  #y = 2;
+
+  constructor(x = 0, y = 0) {
+    this.#x = +x;
+    this.#y = +y;
+  }
+
+  get x() { return this.#x }
+  set x(value) { this.#x = +value }
+
+  get y() { return this.#y }
+  set y(value) { this.#y = +value }
+
+  equals(p) { return this.#x === p.#x && this.#y === p.#y }
+
+  toString() { return `Point<${ this.#x },${ this.#y }>` }
+}