Merge pull request #3257 from horpto/bugfix/T2765

[2765] transform-async-to-generator doesn't work for `this` inside arrow

packages/babel-helper-remap-async-to-generator/src/index.js

@@ -14,11 +14,24 @@ let buildWrapper = template(`
   })
 `);
 
+let arrowBuildWrapper =  template(`
+  (() => {
+    var ref = FUNCTION;
+    return (PARAMS) => ref.apply(this, arguments);
+  })
+`);
+
 let awaitVisitor = {
   Function(path) {
     path.skip();
   },
 
+  ArrowFunctionExpression(path) {
+    if (!path.node.async) {
+      path.arrowFunctionToShadowed();
+    }
+  },
+
   AwaitExpression({ node }) {
     node.type = "YieldExpression";
   }
@@ -42,9 +55,11 @@ function classOrObjectMethod(path: NodePath, callId: Object) {
 
 function plainFunction(path: NodePath, callId: Object) {
   let node = path.node;
+  let wrapper = buildWrapper;
 
   if (path.isArrowFunctionExpression()) {
     path.arrowFunctionToShadowed();
+    wrapper = arrowBuildWrapper;
   }
 
   node.async = false;
@@ -60,7 +75,7 @@ function plainFunction(path: NodePath, callId: Object) {
   }
 
   let built = t.callExpression(callId, [node]);
-  let container = buildWrapper({
+  let container = wrapper({
     FUNCTION: built,
     PARAMS: node.params.map(() => path.scope.generateUidIdentifier("x"))
   }).expression;

packages/babel-plugin-transform-async-to-generator/test/fixtures/async-to-generator/async-arrow-in-method/actual.js

@@ -0,0 +1,10 @@
+let TestClass = {
+  name: "John Doe",
+
+  testMethodFailure() {
+    return new Promise(async (resolve) => {
+      console.log(this);
+      setTimeout(resolve, 1000);
+    });
+  }
+};

packages/babel-plugin-transform-async-to-generator/test/fixtures/async-to-generator/async-arrow-in-method/expected.js

@@ -0,0 +1,15 @@
+let TestClass = {
+  name: "John Doe",
+
+  testMethodFailure() {
+    return new Promise((() => {
+      var _this = this;
+
+      var ref = babelHelpers.asyncToGenerator(function* (resolve) {
+        console.log(_this);
+        setTimeout(resolve, 1000);
+      });
+      return _x => ref.apply(this, arguments);
+    })());
+  }
+};

packages/babel-plugin-transform-async-to-generator/test/fixtures/async-to-generator/deeply-nested-asyncs/actual.js

@@ -0,0 +1,13 @@
+async function s(x) {
+  let t = async (y) => {
+    let r = async (z) =>  {
+      await z;
+      return this.x;
+    }
+    await r;
+
+    return this.g(r);
+  }
+  await t;
+  return this.h(t);
+}

packages/babel-plugin-transform-async-to-generator/test/fixtures/async-to-generator/deeply-nested-asyncs/expected.js

@@ -0,0 +1,28 @@
+let s = function () {
+  var ref = babelHelpers.asyncToGenerator(function* (x) {
+    let t = (() => {
+      var _this2 = this;
+
+      var ref = babelHelpers.asyncToGenerator(function* (y) {
+        let r = (() => {
+          var _this = this;
+
+          var ref = babelHelpers.asyncToGenerator(function* (z) {
+            yield z;
+            return _this.x;
+          });
+          return _x3 => ref.apply(this, arguments);
+        })();
+        yield r;
+
+        return _this2.g(r);
+      });
+      return _x2 => ref.apply(this, arguments);
+    })();
+    yield t;
+    return this.h(t);
+  });
+  return function s(_x) {
+    return ref.apply(this, arguments);
+  };
+}();

packages/babel-plugin-transform-async-to-generator/test/fixtures/async-to-generator/object-method-with-arrows/actual.js

@@ -0,0 +1,6 @@
+class Class {
+  async method() {
+    this;
+    () => this;
+  }
+}

packages/babel-plugin-transform-async-to-generator/test/fixtures/async-to-generator/object-method-with-arrows/expected.js

@@ -0,0 +1,12 @@
+class Class {
+  method() {
+    var _this = this;
+
+    return babelHelpers.asyncToGenerator(function* () {
+      _this;
+      (function () {
+        return _this;
+      });
+    })();
+  }
+}