Improve massageAST (#9519)

src/language-js/clean.js

@@ -1,24 +1,22 @@
 "use strict";
 
-function clean(ast, newObj, parent) {
-  [
-    "range",
-    "raw",
-    "comments",
-    "leadingComments",
-    "trailingComments",
-    "innerComments",
-    "extra",
-    "start",
-    "end",
-    "loc",
-    "flags",
-    "errors",
-    "tokens",
-  ].forEach((name) => {
-    delete newObj[name];
-  });
+const ignoredProperties = new Set([
+  "range",
+  "raw",
+  "comments",
+  "leadingComments",
+  "trailingComments",
+  "innerComments",
+  "extra",
+  "start",
+  "end",
+  "loc",
+  "flags",
+  "errors",
+  "tokens",
+]);
 
+function clean(ast, newObj, parent) {
   if (ast.type === "Program") {
     delete newObj.sourceType;
   }
@@ -210,4 +208,6 @@ function clean(ast, newObj, parent) {
   }
 }
 
+clean.ignoredProperties = ignoredProperties;
+
 module.exports = clean;

src/main/massage-ast.js

@@ -9,15 +9,23 @@ function massageAST(ast, options, parent) {
     return ast;
   }
 
+  const cleanFunction = options.printer.massageAstNode;
+  let ignoredProperties;
+  if (cleanFunction && cleanFunction.ignoredProperties) {
+    ignoredProperties = cleanFunction.ignoredProperties;
+  } else {
+    ignoredProperties = new Set();
+  }
+
   const newObj = {};
   for (const key of Object.keys(ast)) {
-    if (typeof ast[key] !== "function") {
+    if (!ignoredProperties.has(key) && typeof ast[key] !== "function") {
       newObj[key] = massageAST(ast[key], options, ast);
     }
   }
 
-  if (options.printer.massageAstNode) {
-    const result = options.printer.massageAstNode(ast, newObj, parent);
+  if (cleanFunction) {
+    const result = cleanFunction(ast, newObj, parent);
     if (result === null) {
       return;
     }