Fix printing edge cases in Nullish Coalescing and Optional Ch… (#11255)

This is a mix of changes, most importantly:

- Always print parens when mixing nullish coalescing and another logical
- Fixes assignment in the callee of an optional chain, which now blocks #11248

Also, cleans up a bit of code, and removes an unnecessary parens around `class A extends new B {}`

packages/babel-generator/src/node/index.js

@@ -46,14 +46,7 @@ function isOrHasCallExpression(node) {
     return true;
   }
 
-  if (t.isMemberExpression(node)) {
-    return (
-      isOrHasCallExpression(node.object) ||
-      (!node.computed && isOrHasCallExpression(node.property))
-    );
-  } else {
-    return false;
-  }
+  return t.isMemberExpression(node) && isOrHasCallExpression(node.object);
 }
 
 export function needsWhitespace(node, parent, type) {
@@ -97,18 +90,5 @@ export function needsParens(node, parent, printStack) {
     if (isOrHasCallExpression(node)) return true;
   }
 
-  /* this check is for NullishCoalescing being used with LogicalOperators like && and ||
-   * For example when someone creates an ast programmaticaly like this
-   * t.logicalExpression(
-   * "??",
-   *  t.logicalExpression("||", t.identifier("a"), t.identifier("b")),
-   *  t.identifier("c"),
-   *  );
-   * In the example above the AST is equivalent to writing a || b ?? c
-   * This is incorrect because NullishCoalescing when used with LogicalExpressions should have parenthesis
-   * The correct syntax is (a || b) ?? c, that is why we need parenthesis in this case
-   */
-  if (t.isLogicalExpression(node) && parent.operator === "??") return true;
-
   return find(expandedParens, node, parent, printStack);
 }

packages/babel-generator/src/node/parentheses.js

@@ -122,8 +122,6 @@ export function Binary(node: Object, parent: Object): boolean {
       return true;
     }
   }
-
-  return false;
 }
 
 export function UnionTypeAnnotation(node: Object, parent: Object): boolean {
@@ -244,7 +242,8 @@ export function ConditionalExpression(node: Object, parent: Object): boolean {
     t.isBinary(parent) ||
     t.isConditionalExpression(parent, { test: node }) ||
     t.isAwaitExpression(parent) ||
-    t.isOptionalMemberExpression(parent) ||
+    t.isOptionalMemberExpression(parent, { object: node }) ||
+    t.isOptionalCallExpression(parent, { callee: node }) ||
     t.isTaggedTemplateExpression(parent) ||
     t.isTSTypeAssertion(parent) ||
     t.isTSAsExpression(parent)
@@ -272,16 +271,28 @@ export function OptionalCallExpression(node: Object, parent: Object): boolean {
   );
 }
 
-export function AssignmentExpression(node: Object): boolean {
+export function AssignmentExpression(
+  node: Object,
+  parent: Object,
+  printStack: Array<Object>,
+): boolean {
   if (t.isObjectPattern(node.left)) {
     return true;
   } else {
-    return ConditionalExpression(...arguments);
+    return ConditionalExpression(node, parent, printStack);
   }
 }
 
-export function NewExpression(node: Object, parent: Object): boolean {
-  return isClassExtendsClause(node, parent);
+export function LogicalExpression(node: Object, parent: Object): boolean {
+  switch (node.operator) {
+    case "||":
+      if (!t.isLogicalExpression(parent)) return false;
+      return parent.operator === "??" || parent.operator === "&&";
+    case "&&":
+      return t.isLogicalExpression(parent, { operator: "??" });
+    case "??":
+      return t.isLogicalExpression(parent) && parent.operator !== "??";
+  }
 }
 
 // Walk up the print stack to determine if our node can come first

packages/babel-generator/test/fixtures/parentheses/assignment-expression/input.js

@@ -1,3 +1,6 @@
 1 + (a = 2);
 1 + (a += 2);
 a = a || (a = {});
+
+(a = b)();
+(a = b)?.();

packages/babel-generator/test/fixtures/parentheses/assignment-expression/output.js

@@ -1,3 +1,5 @@
 1 + (a = 2);
 1 + (a += 2);
-a = a || (a = {});
+a = a || (a = {});
+(a = b)();
+(a = b)?.();

packages/babel-generator/test/fixtures/parentheses/class-extends/output.js

@@ -12,7 +12,7 @@ class A6 extends class {} {}
 
 class A7 extends (B ? C : D) {}
 
-class A8 extends (new B()) {}
+class A8 extends new B() {}
 
 class A9 extends (B, C) {}
 
@@ -32,4 +32,4 @@ async function f1() {
 
 function* f2() {
   class A16 extends (yield 1) {}
-}
+}

packages/babel-generator/test/fixtures/parentheses/nullish-coalescing/input.js

@@ -1,2 +1,17 @@
 const foo = 'test'
-console.log((foo ?? '') == '')
+console.log((foo ?? '') == '')
+
+
+a ?? (b ?? c);
+(a ?? b) ?? c;
+
+a ?? (b || c);
+a || (b ?? c);
+(a ?? b) || c;
+(a || b) ?? c;
+
+a ?? (b && c);
+a && (b ?? c);
+(a ?? b) && c;
+(a && b) ?? c;
+

packages/babel-generator/test/fixtures/parentheses/nullish-coalescing/output.js

@@ -1,2 +1,12 @@
 const foo = 'test';
-console.log((foo ?? '') == '');
+console.log((foo ?? '') == '');
+a ?? b ?? c;
+a ?? b ?? c;
+a ?? (b || c);
+a || (b ?? c);
+(a ?? b) || c;
+(a || b) ?? c;
+a ?? (b && c);
+a && (b ?? c);
+(a ?? b) && c;
+(a && b) ?? c;

packages/babel-generator/test/fixtures/types/LogicalExpression/input.js

@@ -2,4 +2,14 @@ foo ||bar;
 (x => x)|| bar;
 (function a(x){return x;})|| 2;
 0||(function(){return alpha;});
-a ?? (b || c);
+
+a && (b && c);
+(a && b) && c;
+
+a || (b || c);
+(a || b) || c;
+
+a || (b && c);
+a && (b || c);
+(a || b) && c;
+(a && b) || c;

packages/babel-generator/test/fixtures/types/LogicalExpression/output.js

@@ -9,4 +9,11 @@ foo || bar;
   return alpha;
 };
 
-a ?? (b || c);
+a && b && c;
+a && b && c;
+a || b || c;
+a || b || c;
+a || b && c;
+a && (b || c);
+(a || b) && c;
+a && b || c;