destructuring private fields with array pattern / object pattern

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

@@ -211,6 +211,19 @@ const privateNameHandlerSpec = {
     ]);
   },
 
+  destructureSet(member) {
+    const { privateNamesMap, file } = this;
+    const { name } = member.node.property.id;
+    const { id } = privateNamesMap.get(name);
+    return t.memberExpression(
+      t.callExpression(file.addHelper("classPrivateFieldDestructureSet"), [
+        this.receiver(member),
+        t.cloneNode(id),
+      ]),
+      t.identifier("value"),
+    );
+  },
+
   call(member, args) {
     // The first access (the get) should do the memo assignment.
     this.memoise(member, 1);

packages/babel-helper-member-expression-to-functions/src/index.js

@@ -100,6 +100,34 @@ const handle = {
       return;
     }
 
+    // { KEY: MEMBER } = OBJ -> { KEY: _destructureSet(MEMBER) } = OBJ
+    // { KEY: MEMBER = _VALUE } = OBJ -> { KEY: _destructureSet(MEMBER) = _VALUE } = OBJ
+    // {...MEMBER} -> {..._destructureSet(MEMBER)}
+    //
+    // [MEMBER] = ARR -> [_destructureSet(MEMBER)] = ARR
+    // [MEMBER = _VALUE] = ARR -> [_destructureSet(MEMBER) = _VALUE] = ARR
+    // [...MEMBER] -> [..._destructureSet(MEMBER)]
+    if (
+      // { KEY: MEMBER } = OBJ
+      (parentPath.isObjectProperty({ value: node }) &&
+        parentPath.parentPath.isObjectPattern()) ||
+      // { KEY: MEMBER = _VALUE } = OBJ
+      (parentPath.isAssignmentPattern({ left: node }) &&
+        parentPath.parentPath.isObjectProperty({ value: parent }) &&
+        parentPath.parentPath.parentPath.isObjectPattern()) ||
+      // [MEMBER] = ARR
+      parentPath.isArrayPattern() ||
+      // [MEMBER = _VALUE] = ARR
+      (parentPath.isAssignmentPattern({ left: node }) &&
+        parentPath.parentPath.isArrayPattern()) ||
+      // {...MEMBER}
+      // [...MEMBER]
+      parentPath.isRestElement()
+    ) {
+      member.replaceWith(this.destructureSet(member));
+      return;
+    }
+
     // MEMBER   ->   _get(MEMBER)
     member.replaceWith(this.get(member));
   },

packages/babel-helper-replace-supers/src/index.js

@@ -125,6 +125,12 @@ const specHandlers = {
     ]);
   },
 
+  destructureSet(superMember) {
+    throw superMember.buildCodeFrameError(
+      `Destructuring to a super field is not supported yet.`,
+    );
+  },
+
   call(superMember, args) {
     return optimiseCall(this.get(superMember), t.thisExpression(), args);
   },
@@ -174,6 +180,13 @@ const looseHandlers = {
       value,
     );
   },
+
+  destructureSet(superMember) {
+    const { computed } = superMember.node;
+    const prop = this.prop(superMember);
+
+    return t.memberExpression(t.thisExpression(), prop, computed);
+  },
 };
 
 export default class ReplaceSupers {

packages/babel-helpers/src/helpers.js

@@ -701,7 +701,6 @@ helpers.superPropBase = helper("7.0.0-beta.0")`
 `;
 
 helpers.get = helper("7.0.0-beta.0")`
-  import getPrototypeOf from "getPrototypeOf";
   import superPropBase from "superPropBase";
 
   export default function _get(target, property, receiver) {
@@ -726,7 +725,6 @@ helpers.get = helper("7.0.0-beta.0")`
 `;
 
 helpers.set = helper("7.0.0-beta.0")`
-  import getPrototypeOf from "getPrototypeOf";
   import superPropBase from "superPropBase";
   import defineProperty from "defineProperty";
 
@@ -1104,6 +1102,34 @@ helpers.classPrivateFieldSet = helper("7.0.0-beta.0")`
   }
 `;
 
+helpers.classPrivateFieldDestructureSet = helper("7.4.4")`
+  export default function _classPrivateFieldDestructureSet(receiver, privateMap) {
+    if (!privateMap.has(receiver)) {
+      throw new TypeError("attempted to set private field on non-instance");
+    }
+    var descriptor = privateMap.get(receiver);
+    if (descriptor.set) {
+      if (!("__destrObj" in descriptor)) {
+        descriptor.__destrObj = {
+          set value(v) {
+            descriptor.set.call(receiver, v)
+          },
+        };
+      }
+      return descriptor.__destrObj;
+    } else {
+      if (!descriptor.writable) {
+        // This should only throw in strict mode, but class bodies are
+        // always strict and private fields can only be used inside
+        // class bodies.
+        throw new TypeError("attempted to set read only private field");
+      }
+
+      return descriptor;
+    }
+  }
+`;
+
 helpers.classStaticPrivateFieldSpecGet = helper("7.0.2")`
   export default function _classStaticPrivateFieldSpecGet(receiver, classConstructor, descriptor) {
     if (receiver !== classConstructor) {

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-1/exec.js

@@ -0,0 +1,17 @@
+class Foo {
+  #client
+
+  constructor(props) {
+    this.#client = 1;
+    ;([this.x = this.#client, this.#client, this.y = this.#client] = props);
+  }
+
+  getClient() {
+    return this.#client;
+  }
+}
+
+const foo = new Foo([undefined, 'bar']);
+expect(foo.getClient()).toBe('bar');
+expect(foo.x).toBe(1);
+expect(foo.y).toBe('bar');

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-1/input.js

@@ -0,0 +1,8 @@
+class Foo {
+  #client
+
+  constructor(props) {
+    this.#client = 1;
+    ([this.x = this.#client, this.#client, this.y = this.#client] = props);
+  }
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-1/output.js

@@ -0,0 +1,13 @@
+var Foo = function Foo(props) {
+  "use strict";
+
+  babelHelpers.classCallCheck(this, Foo);
+  Object.defineProperty(this, _client, {
+    writable: true,
+    value: void 0
+  });
+  babelHelpers.classPrivateFieldLooseBase(this, _client)[_client] = 1;
+  [this.x = babelHelpers.classPrivateFieldLooseBase(this, _client)[_client], babelHelpers.classPrivateFieldLooseBase(this, _client)[_client], this.y = babelHelpers.classPrivateFieldLooseBase(this, _client)[_client]] = props;
+};
+
+var _client = babelHelpers.classPrivateFieldLooseKey("client");

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-2/exec.js

@@ -0,0 +1,15 @@
+class Foo {
+  #client
+
+  constructor(props) {
+    let x;
+    ;([x, ...this.#client] = props);
+  }
+
+  getClient() {
+    return this.#client;
+  }
+}
+
+const foo = new Foo(['foo', 'bar', 'baz', 'quu']);
+expect(foo.getClient()).toEqual(['bar', 'baz', 'quu']);

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-2/input.js

@@ -0,0 +1,7 @@
+class Foo {
+  #client
+
+  constructor(props) {
+    ([x, ...this.#client] = props);
+  }
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-2/output.js

@@ -0,0 +1,12 @@
+var Foo = function Foo(props) {
+  "use strict";
+
+  babelHelpers.classCallCheck(this, Foo);
+  Object.defineProperty(this, _client, {
+    writable: true,
+    value: void 0
+  });
+  [x, ...babelHelpers.classPrivateFieldLooseBase(this, _client)[_client]] = props;
+};
+
+var _client = babelHelpers.classPrivateFieldLooseKey("client");

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-3/exec.js

@@ -0,0 +1,14 @@
+class Foo {
+  #client
+
+  constructor(props) {
+    ([this.#client = 5] = props);
+  }
+
+  getClient() {
+    return this.#client;
+  }
+}
+
+const foo = new Foo([]);
+expect(foo.getClient()).toEqual(5);

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-3/input.js

@@ -0,0 +1,7 @@
+class Foo {
+  #client
+
+  constructor(props) {
+    ([this.#client = 5] = props);
+  }
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern-3/output.js

@@ -0,0 +1,12 @@
+var Foo = function Foo(props) {
+  "use strict";
+
+  babelHelpers.classCallCheck(this, Foo);
+  Object.defineProperty(this, _client, {
+    writable: true,
+    value: void 0
+  });
+  [babelHelpers.classPrivateFieldLooseBase(this, _client)[_client] = 5] = props;
+};
+
+var _client = babelHelpers.classPrivateFieldLooseKey("client");

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern/exec.js

@@ -0,0 +1,14 @@
+class Foo {
+  #client
+
+  constructor(props) {
+    ;([this.#client] = props);
+  }
+
+  getClient() {
+    return this.#client;
+  }
+}
+
+const foo = new Foo(['bar']);
+expect(foo.getClient()).toBe('bar');

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern/input.js

@@ -0,0 +1,7 @@
+class Foo {
+  #client
+
+  constructor(props) {
+    ([this.#client] = props);
+  }
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-array-pattern/output.js

@@ -0,0 +1,12 @@
+var Foo = function Foo(props) {
+  "use strict";
+
+  babelHelpers.classCallCheck(this, Foo);
+  Object.defineProperty(this, _client, {
+    writable: true,
+    value: void 0
+  });
+  [babelHelpers.classPrivateFieldLooseBase(this, _client)[_client]] = props;
+};
+
+var _client = babelHelpers.classPrivateFieldLooseKey("client");

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-1/exec.js

@@ -0,0 +1,17 @@
+class Foo {
+  #client
+
+  constructor(props) {
+    this.#client = 'foo';
+    ;({ x: this.x = this.#client, y: this.#client, z: this.z = this.#client } = props)
+  }
+
+  getClient() {
+    return this.#client;
+  }
+}
+
+const foo = new Foo({ y: 'bar' });
+expect(foo.getClient()).toBe('bar');
+expect(foo.x).toBe('foo');
+expect(foo.z).toBe('bar');

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-1/input.js

@@ -0,0 +1,8 @@
+class Foo {
+  #client
+
+  constructor(props) {
+    this.#client = 'foo';
+    ({ x: this.x = this.#client, y: this.#client, z: this.z = this.#client } = props)
+  }
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-1/output.js

@@ -0,0 +1,17 @@
+var Foo = function Foo(props) {
+  "use strict";
+
+  babelHelpers.classCallCheck(this, Foo);
+  Object.defineProperty(this, _client, {
+    writable: true,
+    value: void 0
+  });
+  babelHelpers.classPrivateFieldLooseBase(this, _client)[_client] = 'foo';
+  ({
+    x: this.x = babelHelpers.classPrivateFieldLooseBase(this, _client)[_client],
+    y: babelHelpers.classPrivateFieldLooseBase(this, _client)[_client],
+    z: this.z = babelHelpers.classPrivateFieldLooseBase(this, _client)[_client]
+  } = props);
+};
+
+var _client = babelHelpers.classPrivateFieldLooseKey("client");

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-2-exec/exec.js

@@ -0,0 +1,15 @@
+class Foo {
+  #client
+
+  constructor(props) {
+    let x;
+    ;({ x, ...this.#client } = props)
+  }
+
+  getClient() {
+    return this.#client;
+  }
+}
+
+const foo = new Foo({ x: 'foo', y: 'bar', z: 'baz' });
+expect(foo.getClient()).toEqual({ y: 'bar', z: 'baz' });

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-2-exec/options.json

@@ -0,0 +1,15 @@
+{
+  "plugins": [
+    "transform-destructuring",
+    [
+      "external-helpers",
+      {
+        "helperVersion": "7.4.4"
+      }
+    ],
+    "proposal-class-properties",
+    "transform-classes",
+    "transform-block-scoping",
+    "syntax-class-properties"
+  ]
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-2/input.js

@@ -0,0 +1,7 @@
+class Foo {
+  #client
+
+  constructor(props) {
+    ({ x, ...this.#client } = props)
+  }
+}

packages/babel-plugin-proposal-class-properties/test/fixtures/private-loose/destructuring-object-pattern-2/output.js

@@ -0,0 +1,15 @@
+var Foo = function Foo(props) {
+  "use strict";
+
+  babelHelpers.classCallCheck(this, Foo);
+  Object.defineProperty(this, _client, {
+    writable: true,
+    value: void 0
+  });
+  ({
+    x,
+    ...babelHelpers.classPrivateFieldLooseBase(this, _client)[_client]
+  } = props);
+};
+
+var _client = babelHelpers.classPrivateFieldLooseKey("client");