PR comments

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

@@ -51,11 +51,16 @@ export function NewExpression(node: Object, parent: Object) {
   this.word("new");
   this.space();
   this.print(node.callee, node);
-  if (node.arguments.length === 0 && this.format.minified &&
+  if (this.format.minified &&
+      node.arguments.length === 0 &&
+      !node.optional &&
       !t.isCallExpression(parent, { callee: node }) &&
       !t.isMemberExpression(parent) &&
       !t.isNewExpression(parent)) return;
 
+  if (node.optional) {
+    this.token("?.");
+  }
   this.token("(");
   this.printList(node.arguments, node);
   this.token(")");
@@ -89,6 +94,9 @@ function commaSeparatorNewline() {
 export function CallExpression(node: Object) {
   this.print(node.callee, node);
 
+  if (node.optional) {
+    this.token("?.");
+  }
   this.token("(");
 
   const isPrettyCall = node._prettyCall;

packages/babel-plugin-transform-optional-chaining/README.md

@@ -43,6 +43,8 @@ const baz = obj?.foo?.bar?.baz(); // 42
 const safe = obj?.qux?.baz(); // undefined
 const safe2 = obj?.foo.bar.qux?.(); // undefined
 
+const willThrow = obj?.foo.bar.qux(); // Error: not a function
+
 // Top function can be called directly, too.
 function test() {
   return 42;
@@ -69,6 +71,8 @@ const baz = new obj?.foo?.bar?.baz(); // baz instance
 const safe = new obj?.qux?.baz(); // undefined
 const safe2 = new obj?.foo.bar.qux?.(); // undefined
 
+const willThrow = new obj?.foo.bar.qux(); // Error: not a constructor
+
 // Top classes can be called directly, too.
 class Test {
 }

packages/babel-plugin-transform-optional-chaining/src/index.js

@@ -6,14 +6,11 @@ export default function ({ types: t }) {
     const optionals = [path.node];
     const nil = scope.buildUndefinedNode();
 
-    let objectPath = path.get(key);
-    while (objectPath.isMemberExpression()) {
+    for (let objectPath = path.get(key); objectPath.isMemberExpression(); objectPath = objectPath.get("object")) {
       const { node } = objectPath;
       if (node.optional) {
         optionals.push(node);
       }
-
-      objectPath = objectPath.get("object");
     }
 
     for (let i = optionals.length - 1; i >= 0; i--) {

packages/babel-types/src/definitions/core.js

@@ -119,6 +119,10 @@ defineType("CallExpression", {
     arguments: {
       validate: chain(assertValueType("array"), assertEach(assertNodeType("Expression", "SpreadElement"))),
     },
+    optional: {
+      validate: assertOneOf(true, false),
+      optional: true,
+    },
   },
   aliases: ["Expression"],
 });
@@ -454,6 +458,10 @@ defineType("NewExpression", {
     arguments: {
       validate: chain(assertValueType("array"), assertEach(assertNodeType("Expression", "SpreadElement"))),
     },
+    optional: {
+      validate: assertOneOf(true, false),
+      optional: true,
+    },
   },
 });