add #m?.() support

Co-authored-by: Nicolò Ribaudo <nicolo.ribaudo@gmail.com>

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

@@ -300,7 +300,13 @@ const privateNameHandlerSpec = {
     // The first access (the get) should do the memo assignment.
     this.memoise(member, 1);
 
-    return optimiseCall(this.get(member), this.receiver(member), args);
+    return optimiseCall(this.get(member), this.receiver(member), args, false);
+  },
+
+  optionalCall(member, args) {
+    this.memoise(member, 1);
+
+    return optimiseCall(this.get(member), this.receiver(member), args, true);
   },
 };
 
@@ -328,6 +334,10 @@ const privateNameHandlerLoose = {
   call(member, args) {
     return t.callExpression(this.get(member), args);
   },
+
+  optionalCall(member, args) {
+    return t.optionalCallExpression(this.get(member), args, true);
+  },
 };
 
 export function transformPrivateNamesUsage(

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

@@ -109,7 +109,11 @@ const handle = {
         if (parentPath.isOptionalCallExpression()) {
           // Checking `parent.callee` since we could be in the arguments, eg
           // `bad?.(FOO?.BAR)`.
-          return parent.optional || parent.callee !== node;
+          // Also skip `FOO?.BAR` in `FOO?.BAR?.()` since we need to transform the optional call to ensure proper this
+          return (
+            // In FOO?.#BAR?.(), endPath points the optional call expression so we skip FOO?.#BAR
+            (node !== member.node && parent.optional) || parent.callee !== node
+          );
         }
         return true;
       });
@@ -145,7 +149,9 @@ const handle = {
           continue;
         }
         // prevent infinite loop: unreachable if the AST is well-formed
-        throw new Error("Internal error");
+        throw new Error(
+          `Internal error: unexpected ${startingOptional.node.type}`,
+        );
       }
 
       const { scope } = member;
@@ -163,14 +169,23 @@ const handle = {
       });
       startingOptional.replaceWith(toNonOptional(startingOptional, baseRef));
       if (parentIsOptionalCall) {
-        parentPath.replaceWith(this.call(member, parent.arguments));
+        if (parent.optional) {
+          parentPath.replaceWith(this.optionalCall(member, parent.arguments));
+        } else {
+          parentPath.replaceWith(this.call(member, parent.arguments));
+        }
       } else {
         member.replaceWith(this.get(member));
       }
 
       let regular = member.node;
       for (let current = member; current !== endPath; ) {
         const { parentPath } = current;
+        // skip transforming `Foo.#BAR?.call(FOO)`
+        if (parentPath === endPath && parentIsOptionalCall && parent.optional) {
+          regular = parentPath.node;
+          break;
+        }
         regular = toNonOptional(parentPath, regular);
         current = parentPath;
       }
@@ -299,6 +314,12 @@ const handle = {
       return;
     }
 
+    // MEMBER?.(ARGS) -> _optionalCall(MEMBER, ARGS)
+    if (parentPath.isOptionalCallExpression({ callee: node })) {
+      parentPath.replaceWith(this.optionalCall(member, parent.arguments));
+      return;
+    }
+
     // { KEY: MEMBER } = OBJ -> { KEY: _destructureSet(MEMBER) } = OBJ
     // { KEY: MEMBER = _VALUE } = OBJ -> { KEY: _destructureSet(MEMBER) = _VALUE } = OBJ
     // {...MEMBER} -> {..._destructureSet(MEMBER)}

packages/babel-helper-optimise-call-expression/src/index.js

@@ -1,6 +1,6 @@
 import * as t from "@babel/types";
 
-export default function(callee, thisNode, args) {
+export default function(callee, thisNode, args, optional) {
   if (
     args.length === 1 &&
     t.isSpreadElement(args[0]) &&
@@ -12,6 +12,13 @@ export default function(callee, thisNode, args) {
       args[0].argument,
     ]);
   } else {
+    if (optional) {
+      return t.optionalCallExpression(
+        t.optionalMemberExpression(callee, t.identifier("call"), false, true),
+        [thisNode, ...args],
+        false,
+      );
+    }
     return t.callExpression(t.memberExpression(callee, t.identifier("call")), [
       thisNode,
       ...args,

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

@@ -158,6 +158,7 @@ const specHandlers = {
       this._get(superMember, thisRefs),
       t.cloneNode(thisRefs.this),
       args,
+      false,
     );
   },
 };
@@ -215,7 +216,7 @@ const looseHandlers = {
   },
 
   call(superMember, args) {
-    return optimiseCall(this.get(superMember), t.thisExpression(), args);
+    return optimiseCall(this.get(superMember), t.thisExpression(), args, false);
   },
 };
 

packages/babel-plugin-proposal-class-properties/test/fixtures/private/optional-chain-member-optional-call-with-transform/input.js

@@ -66,9 +66,6 @@ class Foo {
     fn?.().Foo.#self?.getSelf?.()?.self.#m?.();
   }
 
-  static testtest() {
-    fn?.().Foo.#self.getSelf?.().#m?.();
-  }
 }
 
 Foo.test();

packages/babel-plugin-proposal-class-properties/test/fixtures/private/optional-chain-member-optional-call/input.js

@@ -66,9 +66,6 @@ class Foo {
     fn?.().Foo.#self?.getSelf?.()?.self.#m?.();
   }
 
-  static testtest() {
-    fn?.().Foo.#self.getSelf?.().#m?.();
-  }
 }
 
 Foo.test();