Support transforming params of arrow functions in class fields (#13941)

packages/babel-plugin-transform-parameters/src/index.js

@@ -23,6 +23,10 @@ export default declare((api, options) => {
         ) {
           // default/rest visitors require access to `arguments`, so it cannot be an arrow
           path.arrowFunctionToExpression({ noNewArrows });
+
+          // In some cases arrowFunctionToExpression replaces the function with a wrapper.
+          // Return early; the wrapped function will be visited later in the AST traversal.
+          if (!path.isFunctionExpression()) return;
         }
 
         const convertedRest = convertFunctionRest(path);

packages/babel-plugin-transform-parameters/test/fixtures/assumption-noNewArrows-false/default/input.js

@@ -0,0 +1 @@
+let f = (x = 0) => x + 1;

packages/babel-plugin-transform-parameters/test/fixtures/assumption-noNewArrows-false/default/output.js

@@ -0,0 +1,7 @@
+var _this = this;
+
+let f = function f() {
+  let x = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : 0;
+  babelHelpers.newArrowCheck(this, _this);
+  return x + 1;
+}.bind(this);

packages/babel-plugin-transform-parameters/test/fixtures/assumption-noNewArrows-false/options.json

@@ -0,0 +1,6 @@
+{
+  "plugins": ["transform-parameters"],
+  "assumptions": {
+    "noNewArrows": false
+  }
+}

packages/babel-plugin-transform-parameters/test/fixtures/regression/13939-complex/input.js

@@ -0,0 +1,8 @@
+class A extends B {
+  handle = ((x = 0) => {
+    console.log(x, this, new.target, super.y);
+  })(() => {
+    let y = 0;
+    return (x = y) => x + this;
+  })((x = 1) => {})(this);
+}

packages/babel-plugin-transform-parameters/test/fixtures/regression/13939-complex/options.json

@@ -0,0 +1,5 @@
+{
+  "plugins": [
+    "transform-parameters"
+  ]
+}

packages/babel-plugin-transform-parameters/test/fixtures/regression/13939-complex/output.js

@@ -0,0 +1,22 @@
+class A extends B {
+  handle = (() => {
+    var _newtarget = new.target,
+        _superprop_getY = () => super.y,
+        _this = this;
+
+    return function () {
+      let x = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : 0;
+      console.log(x, _this, _newtarget, _superprop_getY());
+    };
+  })()(() => {
+    var _this2 = this;
+
+    let y = 0;
+    return function () {
+      let x = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : y;
+      return x + _this2;
+    };
+  })((() => function () {
+    let x = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : 1;
+  })())(this);
+}

packages/babel-plugin-transform-parameters/test/fixtures/regression/13939-private-complex/input.js

@@ -0,0 +1,8 @@
+class A extends B {
+  #handle = ((x = 0) => {
+    console.log(x, this, new.target, super.y);
+  })(() => {
+    let y = 0;
+    return (x = y) => x + this;
+  })((x = 1) => {})(this);
+}

packages/babel-plugin-transform-parameters/test/fixtures/regression/13939-private-complex/options.json

@@ -0,0 +1,5 @@
+{
+  "plugins": [
+    "transform-parameters"
+  ]
+}

packages/babel-plugin-transform-parameters/test/fixtures/regression/13939-private-complex/output.js

@@ -0,0 +1,22 @@
+class A extends B {
+  #handle = (() => {
+    var _newtarget = new.target,
+        _superprop_getY = () => super.y,
+        _this = this;
+
+    return function () {
+      let x = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : 0;
+      console.log(x, _this, _newtarget, _superprop_getY());
+    };
+  })()(() => {
+    var _this2 = this;
+
+    let y = 0;
+    return function () {
+      let x = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : y;
+      return x + _this2;
+    };
+  })((() => function () {
+    let x = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : 1;
+  })())(this);
+}

packages/babel-plugin-transform-parameters/test/fixtures/regression/13939-private/input.js

@@ -0,0 +1,5 @@
+class A {
+  #handle = (x = 0) => {
+    console.log(x);
+  };
+}

packages/babel-plugin-transform-parameters/test/fixtures/regression/13939-private/options.json

@@ -0,0 +1,5 @@
+{
+  "plugins": [
+    "transform-parameters"
+  ]
+}

packages/babel-plugin-transform-parameters/test/fixtures/regression/13939-private/output.js

@@ -0,0 +1,6 @@
+class A {
+  #handle = (() => function () {
+    let x = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : 0;
+    console.log(x);
+  })();
+}

packages/babel-plugin-transform-parameters/test/fixtures/regression/13939/input.js

@@ -0,0 +1,5 @@
+class A {
+  handle = (x = 0) => {
+    console.log(x);
+  };
+}

packages/babel-plugin-transform-parameters/test/fixtures/regression/13939/options.json

@@ -0,0 +1,5 @@
+{
+  "plugins": [
+    "transform-parameters"
+  ]
+}

packages/babel-plugin-transform-parameters/test/fixtures/regression/13939/output.js

@@ -0,0 +1,6 @@
+class A {
+  handle = (() => function () {
+    let x = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : 0;
+    console.log(x);
+  })();
+}