Class private properties

package.json

@@ -19,7 +19,7 @@
     "babel-preset-flow": "7.0.0-alpha.18",
     "babel-preset-stage-0": "7.0.0-alpha.18",
     "babel-register": "7.0.0-alpha.18",
-    "babylon": "7.0.0-beta.22",
+    "babylon": "7.0.0-beta.24",
     "browserify": "^13.1.1",
     "bundle-collapser": "^1.2.1",
     "chai": "^4.1.0",

packages/babel-core/package.json

@@ -32,7 +32,7 @@
     "babel-template": "7.0.0-beta.1",
     "babel-traverse": "7.0.0-beta.1",
     "babel-types": "7.0.0-beta.1",
-    "babylon": "7.0.0-beta.22",
+    "babylon": "7.0.0-beta.24",
     "convert-source-map": "^1.1.0",
     "debug": "^3.0.1",
     "json5": "^0.5.0",

packages/babel-generator/package.json

@@ -20,6 +20,6 @@
   },
   "devDependencies": {
     "babel-helper-fixtures": "7.0.0-beta.1",
-    "babylon": "^7.0.0-beta.22"
+    "babylon": "^7.0.0-beta.24"
   }
 }

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

@@ -114,6 +114,21 @@ export function ClassProperty(node: Object) {
   this.semicolon();
 }
 
+export function ClassPrivateProperty(node: Object) {
+  if (node.static) {
+    this.word("static");
+    this.space();
+  }
+  this.print(node.key, node);
+  if (node.value) {
+    this.space();
+    this.token("=");
+    this.space();
+    this.print(node.value, node);
+  }
+  this.semicolon();
+}
+
 export function ClassMethod(node: Object) {
   this._classMethodHead(node);
   this.space();

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

@@ -223,3 +223,8 @@ export function MetaProperty(node: Object) {
   this.token(".");
   this.print(node.property, node);
 }
+
+export function PrivateName(node: Object) {
+  this.token("#");
+  this.print(node.id, node);
+}

packages/babel-generator/test/fixtures/types/ClassBody-ClassProperty/actual.js

@@ -26,6 +26,11 @@ class Foo {
   async;
   foo; bar;
   foo = 0; bar = 1;
+
+  #foo;
+  #foo = 1;
+  static #foo;
+  static #foo = Foo.#foo;
 }
 
 class A1 {

packages/babel-generator/test/fixtures/types/ClassBody-ClassProperty/expected.js

@@ -26,6 +26,10 @@ class Foo {
   bar;
   foo = 0;
   bar = 1;
+  #foo;
+  #foo = 1;
+  static #foo;
+  static #foo = Foo.#foo;
 }
 
 class A1 {
@@ -65,4 +69,4 @@ class A6 {
 class A7 {
   static get static() {}
 
-}
+}

packages/babel-generator/test/fixtures/types/ClassBody-ClassProperty/options.json

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

packages/babel-helper-define-map/src/index.js

@@ -61,7 +61,7 @@ export function push(
     key = t.toComputedKey(node, node.key);
   }
 
-  if (t.isObjectProperty(node) || t.isClassProperty(node)) {
+  if (t.isProperty(node)) {
     value = node.value;
   } else if (t.isObjectMethod(node) || t.isClassMethod(node)) {
     value = t.functionExpression(
@@ -131,15 +131,12 @@ export function toClassObject(mutatorMap: Object): Object {
     const propNode = t.objectProperty(map._key, mapNode, map._computed);
 
     Object.keys(map).forEach(function(key) {
-      let node = map[key];
+      const node = map[key];
       if (key[0] === "_") return;
 
-      const inheritNode = node;
-      if (t.isClassMethod(node) || t.isClassProperty(node)) node = node.value;
-
       const prop = t.objectProperty(t.identifier(key), node);
-      t.inheritsComments(prop, inheritNode);
-      t.removeComments(inheritNode);
+      t.inheritsComments(prop, node);
+      t.removeComments(node);
 
       mapNode.properties.push(prop);
     });

packages/babel-helpers/src/helpers.js

@@ -495,6 +495,42 @@ helpers.possibleConstructorReturn = defineHelper(`
   }
 `);
 
+helpers.classPrivateFieldKey = defineHelper(`
+  var id = 0;
+  export default function _classPrivateFieldKey(name) {
+    // Can we use a middle finger emoji?
+    return "__private_" + (id++) + "_" + name;
+  }
+`);
+
+helpers.classPrivateFieldBase = defineHelper(`
+  export default function _classPrivateFieldBase(receiver, privateKey) {
+    if (!Object.prototype.hasOwnProperty.call(receiver, privateKey)) {
+      throw new TypeError("attempted to use private field on non-instance");
+    }
+    return receiver;
+  }
+`);
+
+helpers.classPrivateFieldGet = defineHelper(`
+  export default function _classPrivateFieldGet(receiver, privateMap) {
+    if (!privateMap.has(receiver)) {
+      throw new TypeError("attempted to get private field on non-instance");
+    }
+    return privateMap.get(receiver);
+  }
+`);
+
+helpers.classPrivateFieldPut = defineHelper(`
+  export default function _classPrivateFieldPut(receiver, privateMap, value) {
+    if (!privateMap.has(receiver)) {
+      throw new TypeError("attempted to set private field on non-instance");
+    }
+    privateMap.set(receiver, value);
+    return value;
+  }
+`);
+
 helpers.set = defineHelper(`
   export default function _set(object, property, value, receiver) {
     var desc = Object.getOwnPropertyDescriptor(object, property);

packages/babel-plugin-syntax-class-properties/src/index.js

@@ -1,7 +1,7 @@
 export default function() {
   return {
     manipulateOptions(opts, parserOpts) {
-      parserOpts.plugins.push("classProperties");
+      parserOpts.plugins.push("classProperties", "classPrivateProperties");
     },
   };
 }