Don't use empty obj as default arg value

src/generate.js

@@ -404,7 +404,8 @@ function genRecursion({ref}, state) {
 Given a `CharacterClassRange` node, returns an array of chars that are a case variant of a char in
 the range, and aren't already in the range.
 */
-function getCasesOutsideCharClassRange(node, {firstOnly} = {}) {
+function getCasesOutsideCharClassRange(node, options) {
+  const firstOnly = !!options?.firstOnly;
   const min = node.min.value;
   const max = node.max.value;
   const found = [];

src/parse.js

@@ -457,7 +457,8 @@ function createAssertionFromToken({type, kind, negate}) {
   return node;
 }
 
-function createBackreference(ref, {orphan} = {}) {
+function createBackreference(ref, options) {
+  const orphan = !!options?.orphan;
   return {
     type: AstTypes.Backreference,
     ...(orphan && {orphan}),
@@ -556,7 +557,9 @@ function createFlags({ignoreCase, dotAll, extended}) {
   };
 }
 
-function createGroup({atomic, flags} = {}) {
+function createGroup(options) {
+  const atomic = options?.atomic;
+  const flags = options?.flags;
   return {
     type: AstTypes.Group,
     ...(atomic && {atomic}),
@@ -565,11 +568,16 @@ function createGroup({atomic, flags} = {}) {
   };
 }
 
-function createLookaround({behind = false, negate = false} = {}) {
+function createLookaround(options) {
+  const opts = {
+    behind: false,
+    negate: false,
+    ...options,
+  };
   return {
     type: AstTypes.Assertion,
-    kind: behind ? AstAssertionKinds.lookbehind : AstAssertionKinds.lookahead,
-    negate,
+    kind: opts.behind ? AstAssertionKinds.lookbehind : AstAssertionKinds.lookahead,
+    negate: opts.negate,
     alternatives: [createAlternative()],
   };
 }

src/transform.js

@@ -763,7 +763,8 @@ function isValidGroupNameJs(name) {
 }
 
 // Returns a single node, either the given node or all nodes wrapped in a noncapturing group
-function parseFragment(pattern, {skipPropertyNameValidation} = {}) {
+function parseFragment(pattern, options) {
+  const skipPropertyNameValidation = !!options?.skipPropertyNameValidation;
   const ast = parse(tokenize(pattern), {skipPropertyNameValidation});
   const alts = ast.pattern.alternatives;
   if (alts.length > 1 || alts[0].elements.length > 1) {